Lighting System Cadillac STS I рестайлинг

Fastener Tightening Specifications (NEW)

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DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Starting Point - Lighting

Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic System Check - Vehicle will provide the following information

1. The identification of the control modules which command the system
2. The ability of the control modules to communicate through the serial data circuit
3. The identification of any stored diagnostic trouble codes (DTCs) and their status

The Use of the Diagnostic System Check - Vehicle will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit Description

The suspension position sensors provide the headlamp level controller with front and rear suspension position information. The sensors are permanently grounded and have voltage supplied with the ignition in the ON or CRANK position. The sensors arms are connected to the control arms of the front and rear suspensions. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensors arm. This causes the signal output of the sensors to change. The headlamp level controller compares the information received from the front and rear suspension position sensors and adjusts the headlamp leveling as needed.

Conditions for Running the DTC

The headlamp level controller performs this diagnostic test mode every 51.2 milliseconds when the following conditions are met.

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

Conditions for Setting the DTC

DTC B1010 will set when the headlamp level controller detects a pitch angle that is physically unachievable by the vehicle for 3 consecutive monitoring cycles.

Action Taken When the DTC Sets

When DTC B1010 sets as current, the following actions are taken

1. If the headlamp leveling actuators have positioned the headlamps above the nominal level, the headlamp level controller will drive the headlamps to the nominal setting.
2. If the headlamp leveling actuators have positioned the headlamps below the nominal level, the headlamp level controller will disable the headlamp leveling actuators and maintain the lower than nominal level.

Conditions for Clearing the DTC

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Diagnostic Aids

Reference Information

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the front headlamp leveling suspension position sensor arm from the ball and socket.
2. Ignition ON, observe the scan tool Front Leveling Position Sensor parameter while moving the front suspension position sensor up and down. The reading should change as the arm is moved. If the reading does not change, replace the front suspension position sensor.
3. Connect the front headlamp leveling suspension position sensor arm to the ball and socket
4. Ignition OFF, disconnect the rear headlamp leveling suspension position sensor arm from the ball and socket.
5. Ignition ON, observe the scan tool Rear Leveling Position Sensor parameter while moving the rear suspension position sensor up and down. The reading should change as the arm is moved. If the reading does not change, replace the rear suspension position sensor.
6. If all circuits test normal, replace the headlamp leveling module.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Leveling Front Suspension Height Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Headlamp Leveling Rear Suspension Height Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B1457 02

This DTC will set when the headlamp leveling module detects a short to ground in the left headlamp leveling actuator motor 3 control circuit after 4 consecutive monitoring cycles.

B1457 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the left headlamp leveling actuator motor 3 control circuit after 4 consecutive monitoring cycles.

When DTC B1457 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the left headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 4 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 4 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the left headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B1458 02

This DTC will set when the headlamp leveling module detects a short to ground in the left headlamp leveling actuator motor 4 control circuit after 4 consecutive monitoring cycles.

B1458 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the left headlamp leveling actuator motor 4 control circuit after 4 consecutive monitoring cycles.

When DTC B1458 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the left headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 1 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 1 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the left headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B1459 02

This DTC will set when the headlamp leveling module detects a short to ground in the right headlamp leveling actuator motor 3 control circuit after 4 consecutive monitoring cycles.

B1459 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the right headlamp leveling actuator motor 3 control circuit after 4 consecutive monitoring cycles.

When DTC B1459 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the right headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 4 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 4 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the right headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B1460 02

This DTC will set when the headlamp leveling module detects a short to ground in the right headlamp leveling actuator motor 4 control circuit after 4 consecutive monitoring cycles.

B1460 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the right headlamp leveling actuator motor 4 control circuit after 4 consecutive monitoring cycles.

When DTC B1460 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the right headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 1 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform theHeadlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 1 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the right headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit/System Description

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module determines the ambient light conditions, DAY or NIGHT, based on the voltage from the ambient light sensor. The HVAC control module provides a low reference ground and 5-volt reference signal to the ambient light sensor. The ambient light sensor signal circuit is a direct input to the HVAC control module. The HVAC control module sends a message via serial data to the instrument panel module (IPM) indicating the outside light conditions based on the signal from the ambient light sensor. The IPM determines if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the IPM will command the DRLs ON. During low light conditions the IPM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation. With the turn signal/multifunction switch in the OFF position, the DRLs which consists of the front turn signal lamps will either be turned ON or OFF after a 30-second delay, depending on whether daylight or low light conditions are sensed by the ambient light sensor.

1. The HVAC control module must be powered.
2. DTC B1327 Battery Voltage Low, must not be current.

Ambient light sensor voltage is less than 0.2 volt or greater than 4.9 volts on 3 consecutive tests.

Actions Taken When the DTC Sets

1. The ambient light sensor will default to NIGHT status.
2. The HVAC control module commands the Service A/C System indicator ON via GMLAN serial data.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the sunload sensor assembly.
2. Ignition OFF, scan tool OFF, doors CLOSED, test for less than 20 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
3. Reconnect the sunload sensor assembly harness connector.
4. Ignition ON, verify the scan tool Ambient Light Ssensor parameter is greater than 0.2 volts. If less than the specified range, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the HVAC control module.
5. Verify the scan tool Ambient Light Sensor parameter is less than 4.9 volts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
6. If all circuits test normal, replace the sunload sensor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Sun Load Temperature Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/automatic-hvac-system/#hvac-system-automatic)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B2667 02

This DTC will set when the headlamp leveling module detects a short to ground in the left headlamp leveling actuator motor 1 control circuit after 4 consecutive monitoring cycles.

B2667 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the left headlamp leveling actuator motor 1 control circuit after 4 consecutive monitoring cycles.

When DTC B2667 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the left headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 6 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 6 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 6 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the left headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B2672 02

This DTC will set when the headlamp leveling module detects a short to ground in the left headlamp leveling actuator motor 2 control circuit after 4 consecutive monitoring cycles.

B2672 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the left headlamp leveling actuator motor 2 control circuit after 4 consecutive monitoring cycles.

When DTC B2672 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the left headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 3 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 3 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the left headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B2677 02

This DTC will set when the headlamp leveling module detects a short to ground in the right headlamp leveling actuator motor 1 control circuit after 4 consecutive monitoring cycles.

B2677 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the right headlamp leveling actuator motor 1 control circuit after 4 consecutive monitoring cycles.

When DTC B2677 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the right headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 6 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 6 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 6 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the right headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

The headlamp leveling module performs this diagnostic test mode every 0.8 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

B2682 02

This DTC will set when the headlamp leveling module detects a short to ground in the right headlamp leveling actuator motor 2 control circuit after 4 consecutive monitoring cycles.

B2682 05

This DTC will set when the headlamp leveling module detects an open or short to voltage in the right headlamp leveling actuator motor 2 control circuit after 4 consecutive monitoring cycles.

When DTC B2682 sets, the headlamp leveling module will disable all requests to both headlamp leveling actuators.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the right headlamp leveling actuator.
2. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
3. Ignition OFF, connect a test lamp between the control circuit terminal 3 and the low reference circuit terminal 2.
4. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit terminal 3 for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
5. If all circuits test normal, replace the right headlamp leveling actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The front suspension position sensor provides the headlamp level controller with front suspension position information. The sensor is permanently grounded and has voltage supplied with the ignition in the ON or CRANK position. The sensor arm is connected to the control arm of the front suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arm. This causes the signal output of the sensor to change. The headlamp level controller compares this information with the rear suspension position sensor information and adjusts the headlamp leveling as needed.

The headlamp leveling module performs this diagnostic test mode every 3.2 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

DTC B3410 will set when one of the following conditions occur

B3410 02

The front suspension position sensor voltage reference is less than 4.49 volts for 9.6 milliseconds.

B3410 03

The front suspension position sensor voltage reference is less than 0.5 volt for 9.6 milliseconds.

B3410 07

The front suspension position sensor voltage reference is 4.5 volts or greater for 9.6 milliseconds.

1. The headlamp level controller will turn OFF power to the front suspension position sensor and wait 10 seconds before reapplying power to the sensor. If the reference voltage is less than 4.49 volts, the headlamp level controller will conclude a front suspension position sensor failure has occurred.
2. The headlamp level controller will disable the front suspension position sensor.

B3410 03 and B3410 07

1. If the headlamp leveling actuator has positioned the headlamps above the nominal level, the headlamp level controller will drive the headlamps to the nominal setting.
2. If the headlamp leveling actuator has positioned the headlamps below the nominal level, the headlamp level controller will disable the headlamp leveling actuator and maintain the lower than nominal level.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the LF suspension position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal C. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
4. Verify the scan tool Front Leveling Position Sensor parameter is less than 0.5 volts. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
5. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal A. Verify the scan tool Front Leveling Position Sensor parameter is greater than 4.49 volts. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
6. If all circuits test normal, test or replace the LF suspension position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Leveling Front Suspension Height Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The rear suspension position sensor provides the headlamp level controller with rear suspension position information. The sensor is permanently grounded and has voltage supplied with the ignition in the ON or CRANK position. The sensor arm is connected to the control arm of the rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arm. This causes the signal output of the sensor to change. The headlamp level controller compares this information with the front suspension position sensor information and adjusts the headlamp leveling as needed.

The headlamp leveling module performs this diagnostic test mode every 3.2 millisecond when the following conditions are met

1. The ignition is in the ON or CRANK position.
2. The headlamps are ON.

DTC B3420 will set when one of the following conditions occur

B3420 02

The rear suspension position sensor voltage reference is less than 4.49 volts for 9.6 milliseconds.

B3420 03

The rear suspension position sensor voltage reference is less than 0.5 volt for 9.6 milliseconds.

B3420 07

The rear suspension position sensor voltage reference is 4.5 volts or greater for 9.6 milliseconds.

1. The headlamp level controller will turn OFF power to the rear suspension position sensor and wait 10 seconds before reapplying power to the sensor. If the reference voltage is less than 4.49 volts, the headlamp level controller will conclude a rear suspension position sensor failure has occurred.
2. The headlamp level controller will disable the rear suspension position sensor.

B3420 03 and B3420 07

1. If the headlamp leveling actuator has positioned the headlamps above the nominal level, the headlamp level controller will drive the headlamps to the nominal setting.
2. If the headlamp leveling actuator has positioned the headlamps below the nominal level, the headlamp level controller will disable the headlamp leveling actuator and maintain the lower than nominal level.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 40 consecutive malfunction free ignition cycles have occurred.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the LR suspension position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal C. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
4. Verify the scan tool Rear Leveling Position Sensor parameter is less than 0.5 volts. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
5. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal A. Verify the scan tool Rear Leveling Position Sensor parameter is greater than 4.49 volts. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
6. If all circuits test normal, test or replace the LR suspension position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Leveling Rear Suspension Height Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The instrument panel module (IPM) provides the instrument panel (I/P) dimmer switch with a 5-volt reference voltage and ground. The I/P dimmer switch is a potentiometer that varies the input signal voltage to the IPM. This input determines the intensity level of the back lighting illumination. When the IPM receives the input from the I/P dimmer switch, the IPM will send a serial data message to all control modules that have lamps capable of being dimmed, indicating the ON/OFF status and intensity level of the back lighting. The IPM will default to full intensity if the input from the I/P dimmer switch is not within the specified values.

Battery voltage must be between 9-16 volts.

The IPM detects a short to ground, short to voltage, or an open/high resistance in the I/P lamp dimmer switch signal circuit after 450 milliseconds.

The IPM will default to full intensity if the input from the I/P dimmer switch is not within the specified values.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Interior Lights Dimming Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal 1. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Dimming POT A/D parameter is greater than 140 counts. If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3-A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Dimming POT A/D parameter is less than 30 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the I/P dimmer switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Instrument Panel Lamp Dimmer Switch Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The brake pedal position (BPP) sensor is used to sense the action of the driver's application of the brake pedal. The BPP sensor provides an analog voltage signal that will increase as the brake pedal is applied. The instrument panel module (IPM) provides a low reference signal and a 5-volt reference voltage to the BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the IPM will apply battery voltage to the center high mounted stop lamp (CHMSL), transmission control module (TCM), engine control module (ECM), and stop lamp relay coil. When the stop lamp relay receives battery voltage from the IPM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage through the stop lamps fuse to illuminate the stop lamps.

Battery voltage must be between 9-16 volts.

C0277 03

The DTC will set when the IPM detects an open or short to ground in the BPP sensor circuit for 0.5 second or greater.

C0277 07

The DTC will set when the IPM detects a short to battery voltage in the BPP sensor or low reference circuits for 0.5 second or greater.

C0277 09

The DTC will set when the IPM detects the BPP signal is changing faster than possible under normal operating conditions.

1. The Service Vehicle Soon indicator is commanded ON.
2. When DTC C0277 is set as current, the vehicle will not start.
3. If the DTC sets while the vehicle is running, the IPM will activate the brake lights when the vehicles transmission is not in the PARK position and the vehicle is not accelerating.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 50 malfunction-free ignition cycles have occurred.
3. A DTC will not clear the current status until the next ignition cycle.

If the DTC is set, replace the brake pedal position sensor. If the DTC resets, replace the IPM.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

DTC C0277 03 or C0277 07

1. Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal A. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the IPM.
4. Verify the scan tool BPP Sensor parameter is less than 2 counts. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the IPM.
5. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal C. Verify the scan tool BPP Sensor parameter is greater than 1000 counts. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the IPM.
6. If all circuits test normal, test or replace the brake pedal position sensor.

Verify that DTC C0277 09 is not set.

1. If the DTC is set, perform the brake pedal position sensor recalibration procedure. If the DTC resets, replace the brake pedal position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Brake Pedal Position Sensor Calibration»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
2. «Brake Pedal Position Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The brake pedal position (BPP) sensor is used to sense the action of the driver's application of the brake pedal. The BPP sensor provides an analog voltage signal that will increase as the brake pedal is applied. The instrument panel module (IPM) provides a low reference signal and a 5-volt reference voltage to the BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the IPM will apply battery voltage to the center high mounted stop lamp (CHMSL), transmission control module (TCM), engine control module (ECM), and stop lamp relay coil. When the stop lamp relay receives battery voltage from the IPM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage through the stop lamps fuse to illuminate the stop lamps.

Battery voltage must be between 9-16 volts.

DTC C0278 00 will set when the BPP sensor home position is not learned.

1. The Service Vehicle Soon indicator is commanded ON.
2. When DTC C0278 is set as current, the vehicle will not start.
3. Stop lamps may not activate at the expected brake pedal positions.

1. A successful BBP sensor calibration has been performed.
2. The condition responsible for setting the DTC no longer exists.
3. A history DTC will clear once 50 malfunction-free ignition cycles have occurred.

If DTC C0278 00 is set, recalibrate the BPP sensor.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Verify that DTC C0278 00 is not set.

1. If the DTC is set, perform the brake pedal position sensor recalibration procedure. If the DTC resets, replace the brake pedal position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Brake Pedal Position Sensor Calibration»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
2. «Brake Pedal Position Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The brake pedal position (BPP) sensor is used to sense the action of the driver's application of the brake pedal. The BPP sensor provides an analog voltage signal that will increase as the brake pedal is applied. The instrument panel module (IPM) provides a low reference signal and a 5-volt reference voltage to the BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the IPM will apply battery voltage to the center high mounted stop lamp (CHMSL), transmission control module (TCM), engine control module (ECM), and stop lamp relay coil. When the stop lamp relay receives battery voltage from the IPM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage through the stop lamps fuse to illuminate the stop lamps.

Battery voltage must be between 9-16 volts.

C0870 03

The DTC will set when the IPM detects a short to ground in the brake pedal position sensor voltage reference circuit for 0.5 seconds or greater.

C0870 07

The DTC will set when the IPM detects a short to battery voltage in the brake pedal position sensor voltage reference circuits for 0.5 seconds or greater.

1. The Service Vehicle Soon indicator is commanded ON.
2. If the DTC sets while the vehicle is running, the IPM will activate the brake lights when the vehicles transmission is not in the PARK position and the vehicle is not accelerating.

1. The condition responsible for setting the DTC no longer exists.
2. A history DTC will clear once 50 malfunction-free ignition cycles have occurred.
3. A DTC will not clear the current status until the next ignition cycle.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the brake pedal position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal A. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the IPM.
4. If all circuits test normal, test or replace the brake pedal position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Brake Pedal Position Sensor Calibration»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
2. «Brake Pedal Position Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM replacement, setup, and programming

Symptoms - Lighting

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) before using a symptom table in order to verify that all of the following conditions are true: There are no DTCs set. The control modules can communicate via the serial data link.
2. Review the system description and operation in order to familiarize yourself with the system functions. Refer to the following: «Exterior Lighting Systems Description and Operation»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) «Interior Lighting Systems Description and Operation»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the lighting system. Refer to «Checking Aftermarket Accessories»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__checking-aftermarket-accessories) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Backup Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Courtesy Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Daytime Running Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
4. «Front Fog Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__front-fog-lamps-malfunction)
5. «Rear Fog Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__rear-fog-lamps-malfunction)
6. «Hazard Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__hazard-lamps-malfunction)
7. «Headlamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
8. «Headlamp Leveling Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
9. «Interior Backlighting Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
10. «Lights On Indicator Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
11. «Park, License, and/or Tail Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__park-license-andor-tail-lamps-malfunction)
12. «Stop Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__stop-lamps-malfunction)
13. «Turn Signal Lamps and/or Indicators Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The left rear fuse block supplies battery positive voltage through the REVERSE LAMP fuse to the coil and switch terminals of the reverse lamp relay. The instrument panel module (IPM) sends a power mode message to the rear integration module (RIM) indicating that the ignition is in the RUN position. When the driver places the gear selector in the REVERSE position, the powertrain control module (PCM) sends a message via serial data to the RIM. The RIM provides ground to the reverse lamp relay control circuit which energizes the reverse lamp relay coil. With the reverse lamp relay coil energized, the relay switch contacts close and allow battery voltage to flow from the REVERSE LAMP fuse through the relay switch to illuminate the backup lamps. The backup lamps are permanently grounded at G402.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the reverse lamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the relay controlled output circuit terminal R38 and ground. If the test lamp illuminates, test the relay controlled output circuit for a short to voltage.
3. Verify that a test lamp illuminates between the relay switch B+ circuit terminal R37 and ground. If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the reverse lamp relay.
4. Verify that a test lamp illuminates between the relay coil B+ circuit terminal R36 and ground. If the test lamp does not illuminate, test the relay coil B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative backup lamp.
6. Test for less than 1 ohm between the inoperative backup lamp ground circuit terminal 3 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative backup lamp.
8. Connect a 10A fused jumper wire between the B+ circuit terminal R37 and the control circuit terminal R38. Verify the backup lamps are illuminated. If the backup lamps do not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative backup lamp.
9. Connect a test lamp between the B+ circuit terminal R36 and the control circuit terminal R40.
10. Command the Backup Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the RIM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the RIM.
11. If all circuits test normal, test or replace the reverse lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Backup Lamp Replacement (STS-V)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Backup Lamp Replacement (STS)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
3. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for RIM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The rear integration module (RIM) controls battery positive voltage and ground to the interior courtesy lamps in the following manner. Battery voltage is supplied through the INTERIOR LAMP fuse to both the switch side and coil side of the interior lamp relay. The RIM provides a ground to the control circuit of the interior lamp relay during all power modes except when battery run down protection is active. With the interior lamp relay energized, battery positive voltage is supplied to all the interior lamps in this group. The ground side circuits of the door, footwell, and overhead courtesy lamps are controlled by a pulse width modulated (PWM) ground circuit of the RIM. The RIM pulses the on time of the ground circuit between 0-100 percent at a frequency of approximately 100 hertz. By decreasing the on time percentage of the controlled ground circuit the intensity of the lamps will decrease. This effect is called theater dimming.

Schematic Reference

1. «Release Systems Schematics»(/cadillac/sts/i-2007-2011/remont/door-locks-anti-theft-systems/#door-lock-system-and-door-handles)
2. «Interior Lights Schematics»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Door Lock/Indicator Schematics»(/cadillac/sts/i-2007-2011/remont/door-locks-anti-theft-systems/#door-lock-system-and-door-handles)

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the scan tool Courtesy Lamp Switch parameter while turning the courtesy lamp switch ON and OFF. The reading should toggle between Off and On. If the reading does not change between the commanded states, refer to «Courtesy Lamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__courtesy-lamp-switch-malfunction) .
2. Observe the scan tool Driver Door Open Switch parameter while opening and closing the driver door. The reading should toggle between Open and Closed. If the reading does not change between the commanded states, refer to «Door Open Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__door-open-switch-malfunction) .
3. Observe the scan tool Passenger Door Open Switch parameter while opening and closing the passenger door. The reading should toggle between Open and Closed. If the reading does not change between the commanded states, refer to «Door Open Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__door-open-switch-malfunction) .
4. Observe the scan tool Left Rear Passenger Door Open switch parameter while opening and closing the passenger door. The reading should toggle between Open and Closed. If the reading does not change between the commanded states, refer to «Door Open Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__door-open-switch-malfunction) .
5. Observe the scan tool Right Rear Passenger Door Open switch parameter while opening and closing the passenger door. The reading should toggle between Open and Closed. If the reading does not change between the commanded states, refer to «Door Open Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__door-open-switch-malfunction) .

Courtesy Lamps Malfunction - All

1. Ignition OFF, disconnect the INT LAMP relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R19 and ground. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the RIM.
3. Verify that a test lamp illuminates between the B+ circuit terminal R17 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R19 for a short to ground. If the circuit tests normal, test or replace the INT LAMP relay.
4. Verify that a test lamp illuminates between the B+ circuit terminal R18 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative courtesy lamp.
6. Ignition OFF, scan tool OFF, exterior lamps OFF, interior lamps OFF, test for less than 5 ohms between the control circuit terminal B and ground. If greater than the specified range, test the control circuit for an open/high resistance. If the circuit test normal, replace the RIM.
7. Connect the harness connector at the inoperative courtesy lamp.
8. Connect a 10A fused jumper wire between the B+ circuit terminal R17 and the control circuit terminal R19. Verify the courtesy lamps are ON. If the courtesy lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative courtesy lamp.
9. Connect a test lamp between the B+ circuit terminal R18 and the control circuit terminal R20.
10. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the RIM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the RIM.
11. If all circuits test normal, test or replace the INT LAMP relay.

Door Courtesy Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate door courtesy lamp.
2. Ignition OFF, scan tool OFF, interior lamps OFF, doors CLOSED, test for less than 1 ohm between the control circuit terminal B and ground. If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
3. Connect a test lamp between the control circuit terminal A and the control circuit terminal B.
4. Command the Exterior Courtesy Lamp ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit terminal A for a short to voltage. If the circuit tests normal, replace the appropriate door control module. If the test lamp is always OFF, test the control circuit terminal A for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
5. If all circuits test normal, test or replace the appropriate door courtesy lamp.

Courtesy Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal 1. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the IPM.
3. Ignition ON, verify the scan tool Courtesy Lamp Switch parameter is Off. If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Courtesy Lamp Switch parameter is On. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the I/P dimmer switch.

Door Open Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative door latch assembly.
2. Ignition OFF, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Door Open Switch parameter is Closed. If the not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the appropriate door control module.
4. Install a 3A fused jumper wire between the signal circuit and ground. Verify the scan tool Door Open Switch parameter is Open. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the appropriate door control module.
5. If all circuits test normal, test or replace the inoperative door latch assembly.

Rear Compartment Courtesy Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the rear compartment courtesy lamp.
2. Ignition OFF, doors CLOSED, interior lamps OFF, test for less than 5 ohms between the control circuit terminal C and ground. If greater than the specified range, test the control circuit for an open/high resistance.
3. Ignition OFF, connect a test lamp between the signal circuit terminal B and ground.
4. Command the Trunk Release Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid release actuator. If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the rear compartment lid release actuator.
5. If all circuits test normal, replace the rear compartment courtesy lamp.

Overhead Console Courtesy Lamp Malfunction - Front or Rear

Note. Ignition OFF, disconnect the harness connector at the inoperative overhead console lamp assembly. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 1 ohm between the control circuit terminal B and ground. If greater than the specified range, test the control circuit for an open/high resistance. If the circuit test normal, replace the RIM. Ignition OFF, connect a test lamp between the control circuit terminal A and the control circuit terminal B. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the RIM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the RIM. If all circuits test normal, replace the inoperative overhead console lamp assembly.

I/P Compartment Lamp Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P Compartment lamp switch.
2. Ignition OFF, scan tool OFF, doors CLOSED, interior lamps OFF, test for less than 1 ohm between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition OFF, connect a test lamp between the control circuit terminal B and the ground circuit terminal A.
4. Command the Courtesy Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the test lamp is always ON, test the control circuit for a short to voltage.
5. If all circuits test normal, replace the I/P compartment lamp switch.

Reading Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative vanity mirror.
2. Ignition OFF, scan tool OFF, interior lamps OFF, test for less than 1 ohm between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the control circuit terminal A and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.
4. If all circuits test normal, replace the inoperative reading lamp.

Vanity Mirror Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative vanity mirror.
2. Ignition OFF, scan tool OFF, interior lamps OFF, test for less than 1.0 ohm between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, interior lamps ON, verify that a test lamp illuminates between the control circuit terminal B and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.
4. If all circuits test normal, replace the inoperative vanity mirror.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Rear Compartment Lid Latch Replacement»(/cadillac/sts/i-2007-2011/remont/door-locks-anti-theft-systems/#door-lock-system-and-door-handles)
2. «Rear Door Lock Replacement»(/cadillac/sts/i-2007-2011/remont/door-locks-anti-theft-systems/#door-lock-system-and-door-handles)
3. «Sunshade Replacement»(/cadillac/sts/i-2007-2011/remont/exteriorinterior-trim/#interior-trim-and-paneling)
4. «Rear Compartment Courtesy Lamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
5. «Instrument Panel Lamp Dimmer Switch Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
6. «Overhead Console Courtesy Lamp Replacement (Front)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Overhead Console Courtesy Lamp Replacement (Rear)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
7. «Instrument Panel Courtesy Lamp Bulb Replacement - Right Side»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
8. «Front Side Door Lock Replacement»(/cadillac/sts/i-2007-2011/remont/door-locks-anti-theft-systems/#door-lock-system-and-door-handles)
9. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for DDM, IPM, PDM, LRDM, RRDM, or RIM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ambient light sensor is used to monitor outside lighting conditions. The ambient light sensor provides a voltage signal that will vary between 0.2 and 4.9 volts depending on outside lighting conditions. The HVAC control module determines the ambient light conditions, DAY or NIGHT, based on the voltage from the ambient light sensor. The HVAC control module provides a low reference ground and 5-volt reference signal to the ambient light sensor. The ambient light sensor signal circuit is a direct input to the HVAC control module. The HVAC control module sends a message via serial data to the instrument panel module (IPM) indicating the outside light conditions based on the signal from the ambient light sensor. The IPM determines if outside lighting conditions are correct for either daytime running lights (DRL) or automatic lamp control (ALC) when the headlamp switch is in the AUTO position. In daylight conditions the IPM will command the DRLs ON. During low light conditions the IPM will command the low beam headlamps ON. Any function or condition that turns on the headlamps will cancel DRL operation. With the turn signal/multifunction switch in the OFF position, the DRLs which consists of the front turn signal lamps will either be turned ON or OFF after a 30-second delay, depending on whether daylight or low light conditions are sensed by the ambient light sensor.

Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, verify with a scan tool the Park Brake Switch parameter displays Released.

1. If not the specified value, refer to «Symptoms - Hydraulic Brakes»(/cadillac/sts/i-2007-2011/remont/mechanical-hydraulic/#hydraulic-brake-system__symptoms-hydraulic-brakes)

1. Ignition OFF, disconnect the harness connector at the sunload sensor assembly.
2. Ignition OFF, scan tool OFF, doors CLOSED, test for less than 20 ohms between the low reference circuit terminal C and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
3. Reconnect the sunload sensor assembly harness connector.
4. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 0.2 volt. If less than the specified range, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the HVAC control module.
5. Verify the scan tool Ambient Light Sensor parameter is less than 4.9 volts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
6. If all circuits test normal, replace the sunload sensor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Sun Load Temperature Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/automatic-hvac-system/#hvac-system-automatic)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The front fog lamp relay is supplied with battery voltage at all times. The front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch. The instrument panel module (IPM) energizes the front fog lamp relay by applying ground to the front fog lamp relay control circuit. When the front fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the FOG LAMP fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps.

Schematic Reference

Fog Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool, command the Front Fog Lamps On and Off. The front fog lamps should turn ON and OFF when commanded.

1. If the front fog lamps turn ON and OFF when commanded, refer to «Front Fog Lamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__front-fog-lamp-switch-malfunction) .

Front Fog Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp does not illuminate between B+ and the signal circuit terminal 4. If the test lamp illuminates, test the signal circuit for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3-A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 3. Verify the front fog lamps are illuminated. If the front fog lamps do not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Front Fog Lamps Malfunction

1. Ignition OFF, disconnect the front fog lamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R4 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal R2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R3 for a short to ground. If the circuit tests normal, test or replace the front fog lamp relay.
4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal R1 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative front fog lamp.
6. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal 1 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative front fog lamp.
8. Connect a 15-A fused jumper wire between the B+ circuit terminal R2 and the control circuit terminal R3. Verify the front fog lamps are activated. If the front fog lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative front fog lamp.
9. Connect a test lamp between the B+ circuit terminal R1 and the control circuit terminal R4
10. Command the Front Fog Lamps ON and OFF with the scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the IPM.
11. If all circuits test normal, test or replace the front fog lamp relay.

Front Fog Lamp Indicator Malfunction

Ignition ON, with a scan tool perform the Display Test for the instrument panel cluster (IPC) and observe the front fog lamp indicator.

1. If the front fog lamp indicator illuminates during the test, replace the IPM.
2. If the front fog lamp indicator does not illuminate during the test or remains illuminated at all times, replace the IPC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Fog Lamp Bulb Replacement (STS-V)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Front Fog Lamp Bulb Replacement (STS)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
3. «Relay Replacement (Attached to Wire Harness)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
4. «Turn Signal Multifunction Switch Replacement»(/cadillac/sts/i-2007-2011/remont/steering-column-switches/#steering-wheel-steering-column)
5. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM or IPC replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The rear fog lamp relay is supplied with battery voltage at all times. The rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch. The instrument panel module (IPM) sends a serial data message to the rear integration module (RIM) which energizes the rear fog lamp relay by applying ground to the rear fog lamp relay control circuit. When the rear fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the REAR FOG LAMP fuse to the rear fog lamp supply voltage circuit which illuminates the rear fog lamps.

Schematic Reference

Fog Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool, command the Rear FogLamps On and Off. The rear fog lamps should turn ON and OFF when commanded.

1. If the rear fog lamps turn ON and OFF when commanded, refer to «Rear Fog Lamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__rear-fog-lamp-switch-malfunction) .

Rear Fog Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp does not illuminate between B+ and the signal circuit terminal 2. If the test lamp illuminates, test the signal circuit for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3-A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 3. Verify the rear fog lamps are illuminated. If the rear fog lamps do not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Rear Fog Lamps Malfunction

1. Ignition OFF, disconnect the rear fog lamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R35 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal R32 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R32 for a short to ground. If the circuit tests normal, test or replace the rear fog lamp relay.
4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal R31 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative rear fog lamp.
6. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative rear fog lamp.
8. Connect a 15-A fused jumper wire between the B+ circuit terminal R32 and the control circuit terminal R33. Verify the rear fog lamps are activated. If the rear fog lamps do not activate, test the control circuit terminal R33 for an open/high resistance. If the circuit tests normal, test or replace the inoperative rear fog lamp.
9. Connect a test lamp between the B+ circuit terminal R31 and the control circuit terminal R35
10. Command the Rear Fog lamps ON and OFF with the scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the RIM. If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the RIM.
11. If all circuits test normal, test or replace the rear fog lamp relay.

Rear Fog Lamp Indicator Malfunction

Ignition ON, with a scan tool perform the Display Test for the instrument panel cluster (IPC) and observe the rear fog lamp indicator.

1. If the rear fog lamp indicator illuminates during the test, replace the IPM.
2. If the rear fog lamp indicator does not illuminate during the test or remains illuminated at all times, replace the IPC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
2. «Relay Replacement (Attached to Wire Harness)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
3. «Turn Signal Multifunction Switch Replacement»(/cadillac/sts/i-2007-2011/remont/steering-column-switches/#steering-wheel-steering-column)
4. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM, IPC, or RIM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The hazard flashers may be activated in any power mode. The instrument panel module (IPM) monitors the signal circuit of the hazard switch. When the hazard switch is placed in the ON position, the switch contacts close and battery positive voltage from the IPM flows through the hazard switch to G201. The rear integration module (RIM) turn lamp supply voltage circuit is also provided with ground through the hazard switch when the contacts close at G201 which in turn illuminates the hazard switch LED. The IPM relays the hazard switch status to the rear integration module (RIM) via the serial data circuit. The RIM uses the status of the hazard switch to command the turn signals ON and OFF. The RIM controls both front and rear turn signals. The IPM sends a serial data message to the instrument panel cluster (IPC) to enable both turn signal indicators in an ON and OFF duty cycle when the hazard switch is placed in the ON position. Voltage is supplied to the front and rear turn signals by the RIM. Ground is provided to the front turn signals at G104. The rear turn signals are grounded at G401 and G402.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Hazard Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the hazard switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 2. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Hazard Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Hazard Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the hazard switch.

Hazard Lamp Indicator Malfunction

1. Ignition OFF, disconnect the harness connector at the hazard switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 2. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, park lamps ON, verify that a test lamp illuminates between the circuit terminal 4 and ground. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the RIM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the RIM.
4. If all circuits test normal, test or replace the hazard switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Hazard Warning Switch Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM or RIM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the turn signal/multifunction switch at G200. In response to this input, the instrument panel module (IPM) provides ground to either the headlamp low beam relay control circuit or the headlamp high beam relay control circuit. The position of the headlamp dimmer switch determines which relay coil has ground. The IPM supplies ground to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to both relay switch circuits. When the low beam relay coil is energized, current flows through the LT LOW BEAM and the RT LOW BEAM fuses to the low beam headlamps. The low beam headlamps are grounded at G104. When the headlamp high beam relay coil is energized, current flows through the LT HI BEAM and the RT HI BEAM fuses to the high beam headlamps. The high beam headlamps are also grounded at G104. With the headlamp dimmer switch in the high beam position the IPM sends a message via serial data to the instrument panel cluster (IPC) requesting the IPC to illuminate the high beam indicator.

Schematic Reference

1. «Headlights/Daytime Running Lights (DRL) Schematics»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Inside Rearview Mirror Schematics»(/cadillac/sts/i-2007-2011/remont/mirrors/#mirror-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the scan tool Headlamp Switch parameter while turning the headlamp switch ON and OFF. The parameter should change between On and Off. If the parameter does not change between the commanded states, refer to «Headlamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__headlamp-switch-malfunction) .
2. Observe the scan tool Headlamp/Park Lamp Off Switch parameter while turning the headlamp switch from the PARK and HEAD positions to the OFF position. The parameter change between On and Off. If the parameter does not change between the commanded states, refer to «Headlamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__headlamp-switch-malfunction) .
3. Observe the scan tool Flash to Pass Switch parameter while applying and releasing the flash to pass switch. The parameter should change between Active and Inactive. If the parameter does not change between the commanded states, refer to «Headlamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__headlamp-switch-malfunction) .
4. Observe the scan tool High Beam Select Switch parameter while applying and releasing the high beam select switch. The parameter should change between Active and Inactive. If the parameter does not change between the commanded states, refer to «Headlamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__headlamp-switch-malfunction) .

Headlamp Switch Malfunction

1. Ignition OFF, disconnect the X3 and X4 harness connectors at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal K. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal B. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
4. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal D. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
5. Ignition ON, verify the scan tool Headlamp Switch parameter is Off. If not the specified value, test the signal circuits at terminal N and terminal L for shorts to ground. If the circuits test normal, replace the IPM.
6. Verify the scan tool Flash to Pass switch parameter is Inactive. If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the IPM.
7. Verify the scan tool High Beam Select Switch parameter is Inactive. If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the IPM.
8. Install a 3A fused jumper wire between the signal circuit terminal N and ground. Verify the scan tool Headlamp Switch parameter is On. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
9. Install a 3A fused jumper wire between the signal circuit terminal L and ground. Verify the scan tool Headlamp Switch parameter is On. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
10. Install a 3A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool Flash to Pass Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
11. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool High Beam Select Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
12. If all circuits test normal, test or replace the turn signal/multifunction switch.

Headlamps Malfunction - Low Beam

1. Ignition OFF, disconnect the low beam relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R25 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal R24 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R25 for a short to ground. If the circuit tests normal, test or replace the low beam relay.
4. Verify that a test lamp illuminates between the B+ circuit terminal R26 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative low beam headlamp.
6. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative low beam headlamp.
8. Connect a 40A fused jumper wire between the B+ circuit terminal R24 and the control circuit terminal R25. Verify the low beam headlamps are activated. If the low beam headlamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative low beam headlamp.
9. Connect a test lamp between the B+ circuit terminal R26 and the control circuit terminal R23.
10. Command the Low Beam Headlamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
11. If all circuits test normal, test or replace the low beam relay.

Headlamps Malfunction - High Beam (Standard)

1. Ignition OFF, disconnect the high beam relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R29 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal R28 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R29 for a short to ground. If the circuit tests normal, test or replace the high beam relay.
4. Verify that a test lamp illuminates between the B+ circuit terminal R30 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative high beam headlamp.
6. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative high beam headlamp.
8. Connect a 20A fused jumper wire between the B+ circuit terminal R28 and the control circuit terminal R29. Verify the high beam headlamps are activated. If the high beam headlamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative high beam headlamp.
9. Connect a test lamp between the B+ circuit terminal R30 and the control circuit terminal R27.
10. Command the High Beam Headlamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
11. If all circuits test normal, test or replace the high beam relay.

Headlamps Malfunction - High Beam (Intellibeam)

1. Ignition ON, activate the intellibeam feature and observe the intellibeam indicator located on the inside rearview mirror (ISRVM). The indicator should flash 1 time to indicate the system has been activated. If the indicator flashes more than 3 times, replace the ISRVM.
2. Ignition OFF, disconnect the harness connector at the inside rearview mirror (ISRVM).
3. Connect a test lamp between B+ and the relay control circuit terminal 3.
4. Command the High Beam Headlamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. Connect a test lamp between B+ and the control circuit terminal 4.
6. Ignition ON, verify the test lamp illuminates with the sunload sensor covered and the headlamp switch in the AUTO position. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
7. Ignition OFF, disconnect the harness connector at the automatic headlamp dimming relay.
8. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
9. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal 85 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
10. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
11. Disconnect the harness connector at the inoperative high beam headlamp.
12. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
13. Connect the harness connector at the inoperative high beam headlamp.
14. Connect a 10A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the high beam headlamps are activated. If the high beam headlamps do not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the inoperative high beam headlamp. If the high beam headlamps illuminate, test the signal circuit terminal 86 for a short to voltage, short to ground or an open/high resistance. If the circuit tests normal, replace the ISRVM.
15. If all circuits test normal, test or replace the automatic headlamp dimming relay.

High Beam Indicator Malfunction (Standard)

Ignition ON, with a scan tool perform the Display Test for the instrument panel cluster (IPC) and observe the high beam indicator.

1. If the high beam indicator illuminates during the test, replace the IPM.
2. If the high beam indicator does not illuminate during the test or remains illuminated at all times, replace the IPC.

High Beam Indicator Malfunction (Intellibeam)

1. Ignition ON, with a scan tool perform the Display Test for the instrument panel cluster (IPC) and observe the high beam indicator. The high beam indicator should illuminate during the test and then turn OFF. If the high beam indicator does not illuminate or remains illuminated at all times, replace the IPC.
2. Ignition ON, place the headlamp dimmer switch in the high beam position and observe the high beam indicator. The indicator should illuminate. If the high beam indicator does not illuminate, replace the IPM.
3. Ignition OFF, disconnect the harness connector at the inside rearview mirror (ISRVM).
4. Test the control circuit terminal 1 for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the ISRVM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Bulb Replacement (HID Hi Beam)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Headlamp Bulb Replacement (HID Lo Beam)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Headlamp Bulb Replacement (Lo Beam)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Headlamp Bulb Replacement (Hi Beam)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Underhood Electrical Center or Junction Block Replacement»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
3. «Relay Replacement (Attached to Wire Harness)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
4. «Turn Signal Multifunction Switch Replacement»(/cadillac/sts/i-2007-2011/remont/steering-column-switches/#steering-wheel-steering-column)
5. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM, IPC, or ISRVM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling module monitors the headlamp leveling actuator motor control circuits for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored in memory.

When one of the suspension position sensor voltage reference or sensor signal circuits are shorted to ground, it may not be possible to determine which suspension position sensor voltage reference or sensor signal circuits, front or rear, has failed. If this condition occurs, all suspension position sensor voltage reference and sensor signal circuits will have to be tested for a short to ground.

Schematic Reference

Headlight Leveling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool perform the Headlamp Motor Test and observe the headlamps. Both headlamps should move UP and DOWN as the test is performed.

1. If both head lamps do not move UP and DOWN when commanded, refer to «Headlamp Leveling Actuator Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__headlamp-leveling-actuator-malfunction) .
2. If both head lamps move UP and DOWN when commanded, refer to «Suspension Position Sensor Malfunction - Front»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__suspension-position-sensor-malfunction-front) or «Suspension Position Sensor Malfunction - Rear»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__suspension-position-sensor-malfunction-rear) .

Headlamp Leveling Actuator Malfunction

1. Ignition OFF, disconnect the harness connector at the headlamp leveling module.
2. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal 24 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, test for B+ between the voltage circuit terminal 12 and ground. If less than the specified range, test the voltage circuit for a short to ground or an open/high resistance.
4. Ignition OFF, connect the headlamp leveling control module harness connector.
5. Disconnect the harness connector at the inoperative headlamp leveling actuator.
6. Ignition ON, verify that a test lamp illuminates between the low reference circuit terminal 2 and B+. If the test lamp does not illuminate, test the low reference circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
7. Ignition OFF, connect a test lamp between the control circuit terminal 1 and the low reference circuit terminal 2.
8. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
9. Ignition OFF, connect a test lamp between the control circuit terminal 3 and the low reference circuit terminal 2.
10. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
11. Ignition OFF, connect a test lamp between the control circuit terminal 4 and the low reference circuit terminal 2.
12. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
13. Ignition OFF, connect a test lamp between the control circuit terminal 6 and the low reference circuit terminal 2.
14. Ignition ON, headlamps ON, perform the Headlamp Motor Test with a scan tool. The test lamp should turn ON then OFF as the motor test is performed. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
15. If all circuits test normal, replace the inoperative headlamp leveling actuator.

Suspension Position Sensor Malfunction - Front

1. Ignition OFF, disconnect the harness connector at the LF suspension position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal C. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
4. Verify the scan tool Front Leveling Position Sensor parameter is less than 0.5 volts. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
5. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal A. Verify the scan tool Front Leveling Position Sensor parameter is greater than 4.49 volts. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
6. If all circuits test normal, test or replace the LF suspension position sensor.

Suspension Position Sensor Malfunction - Rear

1. Ignition OFF, disconnect the harness connector at the LR suspension position sensor.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal C. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
4. Verify the scan tool Rear Leveling Position Sensor parameter is less than 0.5 volts. If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the headlamp leveling module.
5. Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit terminal A. Verify the scan tool Rear Leveling Position Sensor parameter is greater than 4.49 volts. If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp leveling module.
6. If all circuits test normal, test or replace the LR suspension position sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Headlamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Headlamp Leveling Front Suspension Height Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Headlamp Leveling Rear Suspension Height Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
4. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for headlamp leveling module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When the park lamp switch is in the ON position, the instrument panel module (IPM) energizes the park lamp relay. With the park lamp relay energized, battery positive voltage is supplied through the DIMMING fuse to the instrument panel lamp fuse supply voltage circuit of the IPM. Upon receiving this voltage supply the IPM requests the status of the ambient light sensor from the climate control panel (CCP). The CCP sends a serial data message indicating a Light or Dark status of the ambient light sensor. The IPM will default to dark if the message is not received. If the status of the ambient light sensor is light, then the interior back lighting will not be activated. The IPM also receives an input from the instrument panel (I/P) dimmer switch. The IPM provides the I/P dimmer switch with a 5-volt reference voltage and ground. The I/P dimmer switch is a potentiometer that varies the input signal voltage to the IPM between 0.36-4.23 volts. This input determines the intensity level of the back lighting illumination. The driver may change intensity of the back lighting by positioning the I/P dimmer switch between the minimum and maximum settings. The IPM will default to full intensity if the input from the I/P dimmer switch is not within the specified values. Upon receipt of all the fore mentioned information, the IPM sends a serial data message to the CCP, IPC, radio, and all the door modules indicating the ON/OFF status and intensity level of the back lighting. The CCP, IPC, and radio incorporate vacuum fluorescent (VF) lamps that are illuminated at full intensity with the ignition in the ON position. The CCP, IPC, and radio will adjust the VF lamp intensity as requested by the IPM by varying the pulse width modulation of the power feed circuit to the VF lamps. When the door control modules receive the serial data message, each door module will supply pulse width modulation (PWM) voltage to the door switch LEDs at the requested intensity. The IPM also supplies voltage to all the remaining lamps at the proper PWM voltage to achieve the requested intensity. The PRNDL incorporates LED lamps that are illuminated at full intensity with the ignition in the ON position. When the park lamps are active, the IPC will adjust the PRNDL LED intensity as requested by the IPM by varying the pulse width modulation of the LED dimming signal circuit to the lamps. All interior back lighting lamps are permanently grounded.

Schematic Reference

Interior Lights Dimming Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Interior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Dimming Pot A/D parameter while operating the dimmer switch from high to low brightness. The parameter should change from a high count to a low count as the switch is activated.

1. If the parameter does not change, refer to «Dimmer Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__dimmer-switch-malfunction) .
2. If the parameter does change, refer to «Interior Backlighting Malfunction - Incandescent»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__interior-backlighting-malfunction-incandescent) .

Dimmer Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P Dimmer switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the low reference circuit terminal 1. If the test lamp does not illuminate, test the low reference circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Dimming POT A/D parameter is greater than 140 counts. If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3-A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Dimming POT A/D parameter is less than 30 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the I/P dimmer switch.

Interior Backlighting Malfunction - Incandescent

1. Ignition OFF, disconnect the X1 harness connector at the IPM.
2. Ignition ON, park lamps ON, verify that a test lamp illuminates between the park lamp voltage supply circuit terminal 1 and ground. If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance.
3. Ignition ON, park lamps OFF, verify that a test lamp does not illuminate between the control circuit terminal 1 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
4. Ignition OFF, disconnect the harness connector at the component with the inoperative backlighting.
5. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
6. Connect a test lamp between the control circuit and ground.
7. Command the Incandescent Dimming Control ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the IPM.
8. If all circuits test normal, test or replace the component with the inoperative incandescent backlighting.

Interior Backlighting Malfunction - LED

1. Ignition OFF, disconnect the harness connector at the component with the inoperative LED backlighting.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the LED dimming control circuit and ground.
4. Command the LED dimming control ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
5. If all circuits test normal, test or replace the component with the inoperative LED backlighting.

Door Switch/Rear Compartment Release Switch Indicator Malfunction

1. Ignition OFF, disconnect the harness connector at the component with the inoperative backlighting.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the backlight lamp control circuit and ground.
4. Command the appropriate door module Door Switch Backlighting ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate door control module. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the appropriate door control module.
5. If all circuits test normal, test or replace the component with the inoperative backlighting.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Electronic Traction Control Switch Replacement»(/cadillac/sts/i-2007-2011/remont/anti-locktraction-control/#antilock-brake-system)
2. «Radio Replacement»(/cadillac/sts/i-2007-2011/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
3. «Hazard Warning Switch Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
4. «Instrument Panel Lamp Dimmer Switch Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
5. «Transmission Floor Shift Control Indicator Lamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
6. «Sunroof Switch Replacement»(/cadillac/sts/i-2007-2011/remont/sun-rooft-topconvertible-top/#sunroof-system)
7. «Steering Wheel Replacement»(/cadillac/sts/i-2007-2011/remont/steering-column-switches/#steering-wheel-steering-column)
8. «Automatic Transmission Control Indicator Replacement»(/cadillac/sts/i-2007-2011/remont/automatic-trans/#how-to-overhaul-the-automatic-transmission-6l506l80-removal-installation-service-troubleshooting-diagnosis)
9. «Steering Wheel Control Switch Assembly Replacement»(/cadillac/sts/i-2007-2011/remont/memory-modules/#secondary-and-configurable-customer-controls)
10. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for DDM, HVAC, IPM, PDM, RRDM, or LRDM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the turn signal/multifunction switch at G200. In response to this input, the instrument panel module (IPM) provides ground to either the headlamp low beam relay control circuit or the headlamp high beam relay control circuit. The position of the headlamp dimmer switch determines which relay coil has ground. The IPM supplies ground to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to both relay switch circuits. When the low beam relay coil is energized, current flows through the LT LOW BEAM and the RT LOW BEAM fuses to the low beam headlamps. The low beam headlamps are grounded at G104. When the headlamp high beam relay coil is energized, current flows through the LT HI BEAM and the RT HI BEAM fuses to the high beam headlamps. The high beam headlamps are also grounded at G104. With the headlamp dimmer switch in the high beam position the IPM sends a message via serial data to the instrument panel cluster (IPC) requesting the IPC to illuminate the high beam indicator. The IPM will also request the IPC to turn on the LIGHTS ON INDICATOR located in the driver information center (DIC) anytime the headlamps are ON and the ignition is OFF or the driver door is opened.

This diagnostic procedure assumes that the headlamps operate as described in Exterior Lighting Systems Description and Operation .

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, with a scan tool perform the Display Test for the instrument panel cluster (IPC) and observe the lights on indicator.

1. If the lights on indicator illuminates during the test, replace the IPM.
2. If the lights on indicator does not illuminate during the test or remains illuminated at all times, replace the IPC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for IPM or IPC replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The park, tail, license, and marker lamps are turned ON when the headlamp switch is placed in the park lamp or headlamp position or anytime the headlights are requested. The park lamps are also turned ON with the front fog lamps. When the ignition switch is in the ON position, the instrument panel module (IPM) provides ground to the controlled voltage circuit of the park lamp relay coil. The underhood fuse block supplies battery voltage to the switch contacts of the park lamp relay. When the headlamp switch is placed in the park lamp or headlamp positions, the park lamp switch ON signal circuit is provided ground at G200. In response to this signal, the IPM provides ground to the control circuit of the park lamp relay coil, which energizes the relay coil. When the park lamp relay coil is energized, the relay switch contacts close causing current to flow from the park lamp relay to the LIC/Dimming fuse, LT PARK fuse, and to the RT PARK fuse. From these fuses, current flows to the park lamps, license lamps, side marker lamps, and tail lamps. The front park lamps and side marker lamps are grounded at G104. The tail lamps and rear sidemarker lamps are grounded at G401 and G402. The LIC/dimming fuse supplies battery positive voltage to the license lamps and IPM instrument panel lamp fuse supply voltage circuit for interior lamps dimming. The license lamps are grounded at G402.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Park Lamp Switch parameter while cycling the park lamp switch between the ON and OFF positions. The parameter should change between On and Off.

1. If the parameter does not change between the commanded states, refer to «Park Lamp Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__park-lamp-switch-malfunction) .
2. If the parameter does change between the commanded states, refer to «Park, License, and/or Tail Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) .

Park Lamp Switch Malfunction

1. Ignition OFF, disconnect the X3 harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal K. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Park Lamp Switch parameter is Off. If not the specified value, test the signal circuit terminal M for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3A fused jumper wire between the signal circuit terminal M and ground. Verify the scan tool Park Lamp Switch parameter is On. If not the specified value, test the signal circuit terminal M for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Park, License, and/or Tail Lamps Malfunction

1. Ignition OFF, remove the fuse of the inoperative park/marker/license lamps and inspect. If the fuse is OPEN, test the control circuit of the blown fuse for a short to ground.
2. Ignition OFF, connect the fuse and disconnect the park lamp relay.
3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R33 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
4. Verify that a test lamp illuminates between the B+ circuit terminal R32 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R33 for a short to ground. If the circuit tests normal, test or replace the park lamp relay.
5. Verify that a test lamp illuminates between the B+ circuit terminal R31 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
6. Disconnect the harness connector at the inoperative park/marker/license lamp.
7. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit and ground If greater than the specified range, test the ground circuit for an open/high resistance.
8. Connect the harness connector at the inoperative park/marker/license lamp.
9. Connect a 30A fused jumper wire between the B+ circuit terminal R32 and the control circuit terminal R33. Verify the park/marker/license lamps are activated. If the park/marker/license lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative park/marker/license lamp.
10. Connect a test lamp between the B+ circuit terminal R31 and the control circuit terminal R34.
11. Command the Park Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
12. If all circuits test normal, test or replace the park lamp relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Side Marker Lamp Replacement (STS)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Front Side Marker Lamp Replacement (STS-V)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Rear Side Marker Lamp Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Front Parking and Turn Signal and Fog Lamp Assembly Replacement (STS-V)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Front Parking and Turn Signal and Fog Lamp Assembly Replacement (STS)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
4. «Relay Replacement (Attached to Wire Harness)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
5. «Turn Signal Multifunction Switch Replacement»(/cadillac/sts/i-2007-2011/remont/steering-column-switches/#steering-wheel-steering-column)
6. «Front Side Marker Lamp Bulb Replacement (STS)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Front Side Marker Lamp Bulb Replacement (STS-V)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
7. «Rear Side Marker Lamp Bulb Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
8. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP sensor provides an analog voltage signal that will increase as the brake pedal is applied. The instrument panel module (IPM) provides a low reference signal and a 5-volt reference voltage to the BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the IPM will apply battery voltage to the center high mounted stop lamp (CHMSL), transmission control module (TCM), engine control module (ECM), and stop lamp relay. When the stop lamp relay receives battery voltage from the IPM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage through the stop lamps fuse to illuminate the stop lamps. Ground for the left stop lamp and CHMSL is provided at G402 and the right stop lamp is grounded at G401.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the scan tool Stop Lamp Status parameter as you apply and unapply the brake pedal. The parameter should change between OFF and ON as the brake pedal is applied and released. If the parameter does not change as the brake pedal is applied and released, refer to «Brake Pedal Position Sensor (BPPS) Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-bpps-malfunction) .
2. With a scan tool, command the Stop Lamps ON and OFF. The stop lamps should turn ON and OFF when changing between the commanded states. If the stop lamps do not illuminate when commanded, refer to «Stop Lamps Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) .

Stop Lamps Malfunction

1. Ignition OFF, disconnect the stop lamp relay.
2. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal R36 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R38 and ground. If the test lamp illuminates, test the control circuit for a short to voltage.
4. Verify that a test lamp illuminates between the B+ circuit terminal R37 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay control circuit terminal R38 for a short to ground. If the circuit tests normal, test or replace the stop lamp relay.
5. Disconnect the harness connector at the inoperative stop lamp.
6. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal D and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative stop lamp.
8. Connect a 10A fused jumper wire between the B+ circuit terminal R37 and the control circuit terminal R38. Verify the stop lamps are activated. If the stop lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative stop lamp.
9. Connect a test lamp between the control circuit terminal R40 and the ground circuit terminal R36.
10. Ignition ON, command the Stop Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
11. If all circuits test normal, test or replace the stop lamp relay.

Center High Mounted Stop Lamp (CHMSL) Malfunction

1. Ignition OFF, disconnect the harness connector at the CHMSL.
2. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
4. Ignition ON, command the Stop Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the IPM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the CHMSL.

Brake Pedal Position Sensor (BPPS) Malfunction

1. Ignition OFF, disconnect the harness connector at the BPPS.
2. Ignition ON, verify that a test lamp does not illuminate between the low reference circuit terminal A and ground. If the test lamp illuminates, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the IPM.
3. Ignition ON, test for 4.8 volts and 5.2 volts between the 5-volt reference circuit terminal C and ground. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the IPM.
4. If all circuits test normal, replace the BPPS.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Brake Pedal Position Sensor Calibration»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
2. «High Mount Stop Lamp Replacement (STS-V)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «High Mount Stop Lamp Replacement (STS)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
3. «Brake Pedal Position Sensor Replacement»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
4. «Relay Replacement (Attached to Wire Harness)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction) or «Relay Replacement (Within an Electrical Center)»(/cadillac/sts/i-2007-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-introduction)
5. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/sts/i-2007-2011/remont/oem-general-information/#vehicle-diagnostic-information-2-of-2__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

With the ignition switch in the RUN position, the turn signal lamps will illuminate when the driver places the turn signal switch in the right or left positions. The instrument panel module (IPM) monitors the signal circuit of the turn signal/multifunction switch. The IPM relays the turn signal switch status to the rear integration module (RIM) via serial data. The RIM uses the status of the turn signal switch to command the turn signals ON and OFF. The RIM controls both front and rear turn signals. The IPM also sends a serial data message to the instrument panel cluster (IPC) to enable the turn signal indicators located in the IPC ON and OFF depending on the position of the turn signal switch. Voltage is supplied to the front and rear turn signals by the RIM. Ground is provided to the front turn signals at G104. The rear turn signals are grounded at G401 and G402. The turn signal/multifunction switch is grounded at G200.

The tail lamp outage detection circuits are low current B+ circuits supplied by the BCM. For purposes of testing, a test lamp connected between the outage detection circuit and ground will not illuminate due to the low current.

Schematic Reference

Exterior Lights Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/cadillac/sts/i-2007-2011/remont/body-electrical/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the scan tool Right and Left Turn/Hazard Lamp Command parameters while cycling the turn signal switch between the left and right positions. The parameters should change between On and Off. If the parameters do not change between the commanded states, refer to «Turn Signal Switch Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__turn-signal-switch-malfunction) . If the parameters change between the commanded states and the turn signal indicators are inoperative, refer to «Turn Signal Indicators Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__turn-signal-indicators-malfunction) .
2. Ignition ON, observe the left turn signal lamps and turn signal indicators on the IPC while activating the left turn signals. The left turn signal lamps and indicators should illuminate and flash when turned ON. If the left turn signal lamps and indictors illuminate but flash in a rapid manner, refer to «Tail Lamp Outage Detection Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__tail-lamp-outage-detection-malfunction) .
3. Ignition ON, observe the right turn signal lamps and turn signal indicators on the IPC while activating the right turn signals. The right turn signal lamps and indicators should illuminate and flash when turned ON. If the left turn signal lamps and indictors illuminate but flash in a rapid manner, refer to «Tail Lamp Outage Detection Malfunction»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__tail-lamp-outage-detection-malfunction) .

Turn Signal Switch Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal G. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Left Front Turn/Hazard Command parameter is Off. If not the specified value, test the signal circuit terminal F for a short to ground. If the circuit tests normal, replace the IPM.
4. Verify the scan tool Right Front Turn/Hazard Command parameter is Off. If not the specified value, test the signal circuit terminal H for a short to ground. If the circuit tests normal, replace the IPM.
5. Install a 3A fused jumper wire between the signal circuit terminal F and ground. Verify the scan tool Left Front Turn/Hazard Command parameter is On. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
6. Install a 3A fused jumper wire between the signal circuit terminal H and ground. Verify the scan tool Right Front Turn/Hazard Command parameter is On. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
7. If all circuits test normal, test or replace the turn signal/multifunction switch.

Turn Signal Lamps Malfunction

1. Ignition OFF, disconnect the harness connector at the inoperative turn signal/repeater lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit and the ground circuit.
4. Command the appropriate turn signal lamp ON and OFF with the turn signal/multifunction switch. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the RIM. If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the RIM.
5. If all circuits test normal, test or replace the appropriate turn signal lamp assembly.

Tail Lamp Outage Detection Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate rear tail lamp assembly.
2. Ignition ON, test for B+ between the outage detection circuit terminal C and ground. If the measured voltage is less than B+, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the RIM.
3. Ignition ON, connect a test lamp between the outage detection circuit terminal C and ground. The test lamp should not Illuminate. If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RIM.
4. If all circuits test normal, test or replace the tail lamp assembly.

Turn Signal Indicators Malfunction

Ignition ON, with a scan tool perform the Display Test for the instrument panel cluster (IPC) and observe the turn signal lamp indicators.

1. If the turn signal lamp indicators illuminate during the test, replace the IPM.
2. If the turn signal lamp indicators do not illuminate during the test or remain illuminated at all times, replace the IPC.

Tail Lamp Assembly

1. Ignition OFF, disconnect the harness connector at the appropriate rear tail lamp assembly.
2. Test for infinite resistance between the outage detection terminal C and the ground terminal D at the tail lamp assembly. If not the specified value, replace the tail lamp assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Parking and Turn Signal and Fog Lamp Assembly Replacement (STS-V)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) or «Front Parking and Turn Signal and Fog Lamp Assembly Replacement (STS)»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system)
2. «Turn Signal Multifunction Switch Replacement»(/cadillac/sts/i-2007-2011/remont/steering-column-switches/#steering-wheel-steering-column)
3. «Control Module References»(/cadillac/sts/i-2007-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for IPC or IPM replacement, setup, and programming

Brake Pedal Position Sensor Calibration

Note. Brake system does not use a brake switch, stoplight switch or brakelight switch. System uses a Brake Pedal Position Sensor to control these functions.

Calibration Criteria

Brake pedal position sensor calibration must be preformed after the brake pedal position sensor or instrument panel module (IPM) have been serviced. The calibration procedure will set brake pedal position sensor home value. This value is used by the IPM to determine the action of the driver applying the brake system and to provide this information to the vehicle subsystems via the GMLAN communication bus.

Calibration Procedure

1. Apply the parking brake.
2. Place the transmission in the PARK position.
3. Install a scan tool.
4. Clear all IPM DTCs before proceeding.
5. Turn ON the ignition, with the engine OFF.
6. Navigate to the Vehicle Control Systems menu.
7. Select Module Setup menu item.
8. Select Instrument Panel Module menu item.
9. Select the BPP Sensor Calibration procedure and follow the directions displayed on the screen.

Removal Procedure

1. Remove the driver side instrument panel (I/P) insulator closeout panel. Refer to «Instrument Panel Insulator Panel Replacement - Left Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Remove the bolt (1) securing the brake pedal position switch to the brake panel bracket.
3. Remove the switch.

Installation Procedure

1. Connect the electrical connector on the switch.
2. Align the brake panel position switch to the stud (3).
3. Install the bolt (1) securing the brake panel position switch to the brake panel bracket and tighten to 9 N.m (80 lb in).
4. Install the driver side I/P insulator closeout panel. Refer to «Instrument Panel Insulator Panel Replacement - Left Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
5. Recalibrate the brake pedal position sensor. Refer to «Brake Pedal Position Sensor Calibration»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) .

1. Remove the defroster grille. Refer to «Defroster Grille Replacement»(/cadillac/sts/i-2007-2011/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .
2. Disconnect the electrical connector (2).
3. Twist the sensor (3) in order to release it from the defroster grille.

1. Install the sensor (3) to the defroster grille.
2. Connect the electrical connector (2).
3. Install the defroster grille. Refer to «Defroster Grille Replacement»(/cadillac/sts/i-2007-2011/remont/automatic-hvac-system/#heating-ventilation-and-air-conditioning) .

Scheme 24

1. Remove the instrument panel (I/P) cluster trim. Refer to «Instrument Cluster Trim Panel Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Release the tabs securing the I/P dimmer switch to the trim.
3. Disconnect the electrical connectors

1. Install the switch to the tabs securing the I/P dimmer switch to the trim.
2. Connect the electrical connectors.
3. Install the I/P cluster trim. Refer to «Instrument Cluster Trim Panel Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .

1. Remove the driver side instrument panel (I/P) closeout/insulator panel. Refer to «Instrument Panel Insulator Panel Replacement - Right Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) or «Instrument Panel Insulator Panel Replacement - Left Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Remove the flasher module (2) off the I/P carrier.
3. Disconnect the electrical connector (1).

1. Connect the electrical connector (1) to the flasher module (2).
2. Slide the flasher module retaining clip onto the I/P carrier.
3. Install the driver side I/P closeout/Insulator panel. Refer to «Instrument Panel Insulator Panel Replacement - Right Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) or «Instrument Panel Insulator Panel Replacement - Left Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .

1. Remove the passenger side instrument panel (I/P) insulator panel. Refer to «Instrument Panel Insulator Panel Replacement - Right Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Disconnect the electrical connector (2).
3. Remove the bulb out of I/P insulator panel.

1. Install the bulb to the I/P insulator panel.
2. Connect the electrical connector (2).
3. Install I/P insulator panel. Refer to «Instrument Panel Insulator Panel Replacement - Right Side»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .

1. Remove the overhead console. Refer to «Roof Console Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Remove the bulb (1) out of the overhead console.

1. Install the bulb (1) to the overhead console.
2. Install the overhead console. Refer to «Roof Console Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .

1. Remove the overhead console. Refer to «Roof Console Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Remove the bulb (1) out of the overhead console.

1. Install the bulb (1) to the overhead console.
2. Install the overhead console. Refer to «Roof Console Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .

Scheme 25

1. Pry the vanity mirror lamp lens (1) in order to remove the lens.
2. Remove the bulb.

1. Install the bulb.
2. Reinstall the vanity mirror lamp lens (1).

1. Remove the shifter bezel. Refer to «Console Shift Lever Bezel Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .
2. Release the tabs (1) on the bottom of the shifter position indicator.
3. Raise the indicator cover in order to access the bulbs mounted on the bottom of the indicator cover.
4. Turn the bulb socket (1) in order to release it from the indicator cover.

1. Locate the bulb socket (1) into the indicator cover.
2. Turn the bulb socket (1) in order to secure it to the indicator cover.
3. Lower the indicator cover onto the shifter assembly.
4. Push the cover in order to secure the tabs (1) on the bottom of the shifter position indicator.
5. Install the shifter bezel. Refer to «Console Shift Lever Bezel Replacement»(/cadillac/sts/i-2007-2011/remont/gauges-instrument-panels/#instrument-panel-trim-and-console-trim) .

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Headlamp Leveling Module Replacement

Replace the headlamp assembly. Refer to Headlamp Replacement .

Refer to Control Module References for programming and setup information.

Scheme 33

Aiming of each of the headlamps is done by turning the vertical (1) adjusting screw which moves the headlamp bulb in relation to the headlamp assembly. The adjusting screw is located inboard of the front fender wheelhouse panel. The high beam will be correctly aimed if the low beam is aimed properly.

Some state and local authorities have specific requirements for aiming the headlamps. These requirements must be followed.

Aiming Area Preparation

Choose an appropriate aiming area, then prepare the aiming screen

1. The aiming area should be darkened and large enough to accommodate the vehicle and an additional 7.62 m (25 ft) measured from the face of the headlamp capsules to the front of the screen.
2. The floor on which the vehicle rests must be flat with the bottom of the screen.
3. The aiming screen should be at least 1.52 m (5 ft) high by 3.66 m (12 ft) wide with a matte white surface well shaded from extraneous light, and properly adjusted to the floor on which the vehicle stands. The screen should be provided with a vertical centerline (3), 2 laterally adjustable vertical tapes (2), and one vertically adjustable horizontal tape (1).
4. The screen must be movable to be aligned parallel with the rear axle of the vehicle. This will allow for a horizontal line drawn perpendicular to the centerline of the screen to pass through the center point between the 2 headlamp capsules (4).
5. After the aiming screen has been set up in a permanent location, paint or tape a reference line on the floor 7.62 m (25 ft) from the screen, to identify the proper location of the headlamp capsules (5) being aimed. If a regular commercial aiming screen is not available, use a vertical wall having a clear uninterrupted area at least 1.83 m (6 ft) high by 3.66 m (12 ft) wide, finished with a washable non-gloss white paint.

Vehicle Preparation

Prepare the vehicle for adjusting the headlamp beam aim

1. Verify that all the components are in place on the vehicle, if other service has been performed on the vehicle.
2. The vehicle must have a full tank of gas.
3. Verify that the tires are inflated to the proper pressures.
4. Stop all other work on the vehicle.
5. Position the vehicle squarely with the aiming screen and with the headlamp directly over the reference line which is painted or taped on the floor.
6. Locate the vertical center line on the aiming screen (3) to be in line with the center of the vehicle (4). This can be accomplished by sighting through the center of the rear window and over the hood. Mark the vertical center of the front and rear windows with narrow tape. Use these marks as sights to locate the centerline of the vehicle. Move the vehicle or the screen until the center line of the screen comes into alignment with the 2 points.
7. Close the doors.
8. Rock the vehicle sideways to stabilize the suspension.
9. Measure the height (6) from the floor to the aiming dots of the headlamps. Adjust the horizontal tape (1) on the aiming screen to match this dimension.
10. Measure the distance (5) between the headlamp aiming dots. Position the vertical tapes (2) this distance equally to the right and left of the centerline.

Headlamp Aiming Procedure

1. Open the hood.
2. Measure from the floor to the center of the headlamp bulb. Some headlamps have an aim dot marked on the headlamp lens.
3. At the screen, measure from the floor and place the horizontal tape at the measured distance.
4. Measure from the reference line on the floor to the left headlamp bulb centerline.
5. At the screen, measure from the reference line and place the vertical tape at the measured distance.
6. Measure from the reference line on the floor to the right headlamp bulb centerline.
7. At the screen, measure from the reference line and place the vertical tape at the measured distance.
8. Turn ON the low beam headlamps and block the light from projecting onto the screen from the passenger side headlamp.
9. Adjust the vertical aim of the headlamps to the specifications required by the state and the local authorities, or as shown in step 8.
10. Rotate the headlamp adjuster (1) to change the vertical aim of the headlamp.
11. Repeat the aiming procedure for the passenger side headlamp while blocking the light from projecting onto the screen from the driver side headlamp.
12. Close the hood.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
2. Remove the right front tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2007-2011/remont/wheel-tire-system/#tires-and-wheels) .
3. Disconnect the electrical connector (1).
4. Disconnect the ball and socket (1) from the vehicle.
5. Remove the bolt (2) from the sensor.
6. Remove the sensor from the vehicle.

1. Position the sensor to the vehicle.
2. Install the bolt (2) to secure the sensor to the vehicle and tighten to 9 N.m (80 lb in).
3. Install the ball and socket (1) to the sensor.
4. Connect the electrical connector (1) to the sensor.
5. Install the right tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2007-2011/remont/wheel-tire-system/#tires-and-wheels) .
6. Lower the vehicle.

1. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(/cadillac/sts/i-2007-2011/remont/hoistjack/#general-information) .
2. Remove the right rear tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2007-2011/remont/wheel-tire-system/#tires-and-wheels) .
3. Disconnect the electrical connector (2).
4. Disconnect the ball and socket (3) from vehicle.
5. Remove the bolt (1) from the sensor.
6. Remove the sensor from the vehicle.

1. Position the sensor (3) to the vehicle.
2. Install the bolt (1) to secure the sensor (4) to the vehicle and tighten to 9 N.m (80 lb in).
3. Install the ball and socket (3) to the sensor (4).
4. Connect the electrical connector (2) to the sensor (4).
5. Install the right tire and wheel assembly. Refer to «Tire and Wheel Removal and Installation»(/cadillac/sts/i-2007-2011/remont/wheel-tire-system/#tires-and-wheels) .
6. Lower the vehicle.

Scheme 34

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Scheme 37

Scheme 38

Fog Lamp Aiming

The front fog lamps must be aimed for proper illumination of the road. The aim should be verified when a when a new fog lamp assembly is installed, or if service or repairs in the front end area may have disturbed the fog lamp mounting surface.

No horizontal adjustment for aiming the front fog lamp assemblies is provided on this vehicle.

1. Use the headlamp aiming screen for aiming the fog lamps. Refer to «Headlamp Aiming»(/cadillac/sts/i-2007-2011/remont/exterior-lights/#lighting-system) .
2. To ensure accurate vertical front fog lamp aiming, first perform the following steps to prepare the vehicle: Ensure that all the components are in place on the vehicle. Ensure that the fuel tank is full. Ensure that the tires are inflated to the proper pressure. Place the vehicle on a level surface 7.6 m (25 ft) away from a target screen. Stop all other operations of work on the vehicle. Jounce the vehicle to settle the suspension. IMPORTANT: Do NOT cover the headlamps. This may cause excessive heat buildup. Block the headlamps from projecting light onto the aiming screen while aiming the fog lamps.
3. Turn the front fog lamps ON.
4. Measure the distance from the centerline of the vehicle (1) to the center of each fog lamp beam (3). These measurement should be the same. If necessary adjust the fog lamp mounting surface.
5. Measure from the center of the fog lamp to the ground line. Using this measurement, mark the horizontal centerline (2) of the fog lamp on the target screen directly in front of the vehicle.
6. The fog lamp vertical adjustment screw is located on the front of the fog lamp.
7. Adjust the fog lamp up or down until the top of the fog lamp beam (4) on the target screen is 102 mm (4 in) below the horizontal centerline (2).
8. Turn OFF the front fog lamps.

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Scheme 52

1. Remove the rear window shelf trim. Refer to «Rear Window Shelf Trim Panel Replacement»(/cadillac/sts/i-2007-2011/remont/exteriorinterior-trim/#interior-trim-and-paneling) .
2. Remove the rear compartment lamp (5).

1. Install the rear compartment lamp (5) the rear carrier.
2. Install the rear window shelf trim. Refer to «Rear Window Shelf Trim Panel Replacement»(/cadillac/sts/i-2007-2011/remont/exteriorinterior-trim/#interior-trim-and-paneling) .

Exterior Lamps

The exterior lighting system consists of the following features

1. Backup lamps
2. Daytime running lamps (DRL)
3. Front fog lamps
4. Hazard lamps
5. Headlamps
6. Park, tail, license, and cornering/side marker lamps
7. Position lamps (Export)
8. Rear fog lamps (Export)
9. Repeater lamps
10. Stop lamps
11. Turn signal lamps

Headlamps

The headlamps consist of 2 interchangeable single filament bulbs or 2 high intensity discharge (HID) arc tubes and ballast on each side of the vehicle which provide high and low beams. The lower bulb in the headlamp is the high beam and the upper bulb is the low beam.

The headlamps may be turned ON in 3 different ways

1. When the headlamp switch is placed in the ON position, for normal operation
2. When the headlamp switch is placed in the AUTO position, for automatic lamp control (ALC)
3. When the headlamp switch is placed in the AUTO position, with the windshield wipers ON in daylight conditions, after a 6 second delay

With the headlamp switch in the ON position, the headlamp switch headlamp ON signal circuit is grounded through the turn signal/multifunction switch at G200. In response to this input, the instrument panel module (IPM) provides ground to either the headlamp low beam relay control circuit or the headlamp high beam relay control circuit. The position of the headlamp dimmer switch determines which relay coil has ground. The IPM supplies ground to the relay coil circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to both relay switch circuits. When the low beam relay coil is energized, current flows through the LT LOW BEAM and the RT LOW BEAM fuses to the low beam headlamps. The low beam headlamps are grounded at G104. When the headlamp high beam relay coil is energized, current flows through the LT HI BEAM and the RT HI BEAM fuses to the high beam headlamps. The high beam headlamps are also grounded at G104. When the headlamp dimmer switch lever is pulled toward the driver, the flash to pass (FTP) switch closes. This grounds the IPM flash to pass switch signal. In response to this input, the IPM energizes the high beam relay. Both high beams will remain ON until the driver releases the headlamp dimmer switch handle. If the low beam headlamps were ON during FTP operation, the low beams remain ON. The headlights may be switched to high beam with the opposite movement of the headlamp dimmer switch lever. With the headlamp dimmer switch in the high beam position the IPM sends a message via GMLAN to the instrument panel cluster (IPC) requesting the IPC to illuminate the high beam indicator. If the headlamp switch is left in the ON position, the inadvertent power control feature will turn OFF the headlights 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the headlights will remain ON until turned OFF or the battery runs dead.

During automatic lamp control (ALC), the headlamps will be in low beam operation during low light conditions. A HEADLAMPS SUGGESTED message will appear on the driver information center (DIC) when the headlamps and park lamps are OFF due to all exterior lighting controls being inactive when dark conditions are sensed. The auto position of the headlamp switch is supplied ground at G200 and enables the auto lamp feature. When the ignition is ON, the IPM will automatically turn the headlamps ON or OFF according to the Light/Dark photocell Status.

The headlamps ON with wipers feature operates when the following conditions are true

1. The ignition is in the RUN position.
2. The headlamps are currently OFF.
3. The headlamp switch is in the AUTO position.
4. The ambient light sensor indicates DAYTIME conditions.

When the headlamps ON with wipers feature is active the DIC will display the HEADLAMPS SUGGESTED message.

Headlamps - High Intensity Discharge (HID)

The high intensity discharge (HID) system is made up of the ballast and arc tube. The headlamp ballast receives the headlamp low beam supply voltage, which would normally be used to directly supply the low beam headlamp. Each ballast has a separate ground. The HID headlamp operation consist of 3 states. The startup or strike state, run up state, and steady state. When the headlamp switch is placed in the ON position, the ballast may draw up to 20 amps. This is referred to as the strike state. The ballast will provide multiple high voltage pulses to the arc tube in order to start the bulb. The voltage provided by the ballast during the startup state ranges from -600 to +600 volts. Once an arc is established, the ballast will provide a higher then steady state voltage to the arc tube in order to keep the bulb illuminated. This is called the run up state. On a cold bulb this state could last as long as 41 seconds. On a hot bulb, the run up state may last as long as 15 seconds. Steady state operation begins when the bulb reaches the 35 watt power level. The ballast provides the bulb with a minimum of 55 volts during steady state operation.

For proper operation of the HID system, ensure the battery and the harness are capable of supplying up to 20 amps of current per ballast, with less than 2 volts of system loss or voltage drop. Each ballast requires up to 20 amps in order to ensure normal startup and run up of the lamp.

The range of white light that is acceptable is broad when compared to halogens. Therefore, some variation in headlight coloring between the right and left headlamp will be normal. Replace the arc tube only if the arc tube is determined to be at the bulb failure stage.

Headlamps - Intellibeam

The intellibeam system operates the high beam headlamps ON and OFF automatically when certain conditions are met and the system is activated. The system consists of a digital light sensor that is located in a separate module that is mounted to the back of the inside rearview mirror. The digital sensor detects light, not vehicle movement. The sensor analyzes light color, intensity, and movement. The intellibeam system will turn OFF the high beam headlamps when other vehicles headlamps or taillights are detected by the digital sensor. Intellibeam can be deactivated when the headlamp dimmer switch is moved from the neutral position to the high beam or flash to pass (FTP) positions. When the headlamp dimmer switch is returned to the neutral position, intellibeam will be enabled.

Intellibeam modulates the high beam headlamps by gradually fading the high beam headlamps ON or OFF. Intellibeam is designed to ignore non-vehicular light sources. However, the system may dim the high beams if it detects lighting or lighting reflections similar in color and intensity to vehicle lighting. When this occurs, intellibeam will dim the high beams until the light or reflection source is no longer detected.

1. The other vehicles lamps are undetectable due to dirt, snow, road spray, smoke, fog, or any other airborne conditions.
2. The vehicle windshield is covered with ice, dirt, snow, haze, or the intellibeam digital light sensor is obstructed.
3. The vehicle ride height is such that the front of the vehicle is pointed upward causing the intellibeam light sensor to be aimed high.
4. The vehicle is being driven on winding or hilly road conditions which would make any on coming vehicle headlamps undetectable by the intellibeam.

Cleaning the intellibeam digital light sensor should be done periodically to ensure system performance. To clean the sensor, use glass cleaner and a soft cloth. Apply the glass cleaner to a soft cloth and gently wipe the light sensor lens. Do not apply the glass cleaner directly to the light sensor lens.

1. The headlamp switch is in the AUTO position.
2. The headlamp dimmer switch must be in the neutral position.
3. Intellibeam has been turned ON by pushing the AUTO button located on the face of the rearview mirror.
4. Outside conditions must be dark.
5. Intellibeam will only function when the vehicle is in DRIVE and moving. Speed Thresholds: Accelerating: As the vehicle is accelerating, intellibeam will gradually apply the high beams when vehicle speed reaches 20 mph (32 km/hr) or greater. Full high beam intensity will not occur until the vehicle has achieved a speed of 25 mph (40 km/hr) or greater. Decelerating: As the vehicle is decelerating, intellibeam will fade the high beams down until they are completely OFF at or below 15 mph (24 km/hr).

1. Intellibeam is automatically disabled each time the vehicle is started. To disable intellibeam after the system has been enabled, press the intellibeam AUTO button on the rearview mirror for 3 seconds and releasing it after the green LED intellibeam status indicator on the left side of the rearview mirror flashes 2 times. When this is done, the intellibeam system will not be active until the system is manually turned ON.
2. Intellibeam is enabled by pressing and releasing the intellibeam AUTO button located on the rearview mirror after the vehicle has been started. The green LED intellibeam status indicator located on the left side of the rearview mirror will flash 1 time to indicate the system has been turned ON.

Intellibeam Demonstration Mode

The intellibeam demonstration mode allows the technician to verify that the intellibeam system components are operating correctly. Perform the intellibeam demonstration mode under daylight conditions only. The following steps detail how to enter the intellibeam demonstration mode.

1. Turn OFF the ignition.
2. While turning the ignition to the ON position, push and hold the intellibeam AUTO button located on the inside rearview mirror (ISRVM) for approximately 8 seconds after the ignition is turned ON. The high beam indicator located on the instrument panel cluster (IPC) will illuminate indicating the demonstration mode is enabled. The demonstration mode will run for approximately 45 seconds. The following actions will take place during the demonstration mode: High Beam Fading - During this mode the high beams will fade from high to low 3 times. The high beam indicator located on the IPC will turn ON as soon as the high beams are energized even thought full intensity has not been achieved. The high beam indicator will not turn OFF until the high beams have faded completely OFF. Intellibeam Light Sensor Status - During this mode, the intellibeam light sensor can be checked by covering the light sensor with a dark cloth. Once the light sensor if fully covered, the green LED intellibeam status indicator located on the left side of the ISRVM will turn OFF. When the light sensor is uncovered, the intellibeam status indicator will turn ON. This check will confirm that the intellibeam light sensor is operating correctly. Intellibeam Enable/Disable Status - Intellibeam can indicate if the system is enabled or disabled. During the intellibeam light sensor check in step 2 above, if intellibeam is disabled, the green LED intellibeam status indicator will flash repeatedly once the light sensor is covered. Once the light sensor is uncovered, the green LED intellibeam status indicator will turn ON.

HID Headlamps Low Voltage Operation

The instrument panel module (IPM) monitors the vehicle system voltage while in the RUN power mode. When the system voltage drops below 8.9 volts, the following will occur

STAGE 1: If the low beam headlamps are ON, whether manually or automatically, the IPM will turn ON the high beam headlamps by activating the flash to pass output control and turn OFF the low beam headlamps.

When the system voltage drops below 8.5 volts, the following will occur

1. STAGE 2: If the low beam headlamps are ON, whether manually or automatically the IPM will turn OFF the low beam headlamps by deactivating the low beam relay output.
2. If the headlamps are turned ON manually, the manual switch redundancy will cause the low beam headlamps to remain ON.
3. If the headlamp dimmer switch is in the HIGH BEAM position, the low beam headlamps will remain ON. The IPM will activate the flash to pass output control.

If during the same ignition cycle the IPM enters either STAGE 1 or STAGE 2 operations noted above, the IPM determines that the system voltage has risen and the following will occur

1. If the IPM has entered STAGE 2 operation, it will not return to STAGE 1 operation until the system voltage rises above 9.4 volts.
2. If the IPM has entered STAGE 1 operation, it will not return to normal operation until the system voltage rises above 9.8 volts.

Automatic Headlamp Leveling - European Only

The Automatic Headlamp Leveling systems consist of the following components

1. Headlamp leveling module
2. Headlamp leveling actuator - left
3. Headlamp leveling actuator - right
4. Suspension position sensor - LF
5. Suspension position sensor - LR

The automatic headlamp leveling system automatically maintains the vertical alignment of the headlamps when the vehicle load and driving conditions change. The headlamp leveling module receives inputs from the front and rear suspension position sensors to determine vehicle pitch. The suspension position sensors send an output to the headlamp leveling module as the vehicle suspension compresses and rebounds. The headlamp leveling module calculates the difference in vehicle pitch and sends a command to the headlamp leveling actuators. The headlamp leveling actuators drive the headlamps to the position commanded by the headlamp leveling module. The headlamp leveling system also monitors the performance of the high intensity discharge (HID) bulb and ballast. When the headlamp switch is placed in the ON position the headlamps will go down, and then back up to the center position.

Daytime Running Lamps (DRL) - North American/Canadian

The daytime running lamps (DRL) consist of the front turn signal lamps illuminated continuously. The DRLs will operate when the following conditions are met

1. The ignition is in the RUN or CRANK position.
2. The shift lever is out of the PARK position.
3. The high and low beam headlamps are OFF.
4. The park brake is not applied.

When conditions for DRL operation exist, the powertrain control module (PCM) sends a message via GMLAN serial data to the instrument panel module (IPM) indicating the transmission has been removed from the PARK position. The ambient light sensor is a light sensitive transistor that varies its voltage signal to the HVAC control module in response to changes to the outside (ambient) light level. When the HVAC control module receives this signal, it communicates via GMLAN with the IPM. The IPM either turns on the right and left front turn signals for DRL operation or the low beam headlamps for auto headlamp operation depending on outside lighting conditions. Any function or condition that turns the headlamps ON will cancel the DRLs operation.

Daytime Running Lamps (DRL) - Norway/Sweden

The daytime running lamps (DRL) consist of the right and left low beam headlamps illuminated continuously and the park lamps. The DRLs will operate when the following conditions are met

1. The ignition is in the RUN or CRANK position.
2. The shift lever is out of the PARK position.
3. The high and low beam headlamps are OFF.
4. The park lamps are OFF.
5. The fog lamps are OFF.
6. The park brake is not applied.

When conditions for DRL operation exist, the powertrain control module (PCM) sends a message via GMLAN serial data to the instrument panel module (IPM) indicating the transmission has been removed from the PARK position. The ambient light sensor is a light sensitive transistor that varies its voltage signal to the HVAC control module in response to changes to the outside (ambient) light level. When the HVAC control module receives this signal it communicates via GMLAN with the IPM. The IPM either turns ON the DRLs using a reduced output or the low beam headlamps at full intensity for auto headlamp operation. Any function or condition that turns the headlamps ON will cancel the DRLs operation. The DRLs consists of the low beam headlamps. With the headlamp switch in the OFF position, the headlamps will either be turned ON or OFF, after an approximate 8 second delay depending on whether daylight or low light conditions are sensed.

Twilight Sentinel

Twilight sentinel is a driver convenience that controls the exterior lamps in response to changes to the outside, ambient light level. The twilight sentinel will also keep the low beam headlamps and park lamps ON for a pre-selected period of time after the ignition is turned to the OFF position when night time conditions are sensed. The twilight delay is programmable through the driver information center (DIC) for Driver 1 and Driver 2.

1. 0 seconds
2. 15 seconds
3. 30 seconds
4. 60 seconds
5. 90 seconds
6. 120 seconds
7. 180 seconds
8. 240 seconds

The DIC will enable the park/headlamp delay feature under the following conditions

1. The time delay is programed to 15 seconds or more for the current driver.
2. The headlamp switch is in the auto position.
3. The automatic headlamp feature has not been canceled.
4. The ambient light sensor status is night time.
5. The ignition is OFF.

The delay timer starts once the ignition is turned OFF. The lights will not turn OFF until the set time has been completed or the keyless entry system receives a request for door unlock or trunk release.

Front Fog Lamps

With the ignition switch in the ON or START position, the front fog lamps will illuminate when the driver toggles the front fog lamp switch to the ON position. The front fog lamp switch is a momentary switch that requires the driver to briefly place the front fog lamp switch to the ON position and release it. The instrument panel module (IPM) controls the front fog lamp relay coil. When the driver toggles the front fog lamp switch to the ON position, the switch supplies ground to the front fog lamp switch signal circuit of the IPM. In response to this input, the IPM supplies ground to the front fog lamp relay control circuit. The underhood fuse block supplies battery positive voltage to the switch circuit of the front fog lamp relay. Ignition voltage is available to the front fog lamp relay coil when the key is in the RUN or CRANK positions. When the IPM grounds the front fog lamp relay control circuit the relay coil energizes, closing the switch contacts. Current then flows from the fog lamp fuse through the front fog lamp relay switch to both front fog lamps. Both front fog lamps are permanently grounded at G104. The front fog lamps will default to the OFF position upon a key cycle.

The IPM will turn the park lamps ON when the front fog lamps are ON and send a message via GMLAN serial data to the instrument panel cluster (IPC) to enable the front fog lamp indicator. The front fog lamps will deactivate when either the flash-to-pass or the high beam headlamps are turned ON. For vehicles exported to Japan or any European Country except Norway or Sweden, the front fog lamps will remain illuminated with the operation of the high beam headlamps or flash-to-pass.

Rear Fog Lamps - European

Rear fog lamps are required equipment on some export vehicles. The rear fog lamps are located in the rear deck lid lamp assembly. The rear fog lamps will only operate when the ignition in the RUN or CRANK positions and either the front fog lamps or headlamps are turned ON. When the driver turns the rear fog lamp switch ON, the switch supplies ground to the rear fog lamp switch signal circuit of the instrument panel module (IPM). In response to this input, the IPM sends a message via GMLAN serial data to the rear integration module (RIM). The RIM responds to this message by grounding the rear fog lamp relay control circuit. When the rear fog lamp relay control circuit is grounded, this energizes the rear fog lamp relay coil causing the switch side contacts to close. Supply voltage from the rear fog lamp fuse flows through the rear fog lamp relay switch to the rear fog lamps. The rear fog lamps have permanent ground at G401. The IPM communicates via GMLAN serial data with the instrument panel cluster (IPC) requesting the rear fog lamp indicator be illuminated. The rear fog lamps will deactivate if the front fog lamps or headlamps are turned OFF, if the ignition is out of the RUN or CRANK position, or if the driver turns the rear fog lamp switch OFF. The rear fog lamps will default to the OFF position upon a key cycle.

Park, Tail, License, and Marker Lamps

The tail, stop, and turn signal functions are performed by the quarter mounted tail lamps. The quarter mounted tail lamps consist of red lenses and light emitting diodes (LED) instead of incandescent bulbs. The tail lamp assemblies wrap around the corners of the vehicle and serve as the rear side marker. The lower portion of each lamp contains reflectors to alert approaching vehicles for night time driving safety. The park, tail, license, and marker lamps are turned ON when the headlamp switch is placed in the park lamp or headlamp position or anytime the headlights are requested. The park lamps are also turned ON with the front fog lamps. When the ignition switch is in the ON position, the instrument panel module (IPM) provides ground to the controlled voltage circuit of the park lamp relay coil. The underhood fuse block supplies battery positive voltage to the switch contacts of the park lamp relay. When the headlamp switch is placed in the park lamp or headlamp positions, the park lamp switch ON signal circuit is provided ground at G200. In response to this signal, the IPM provides ground to the control circuit of the park lamp relay coil, which energizes the relay coil. When the park lamp relay coil is energized, the relay switch contacts close causing current to flow from the park lamp relay to the LIC/Dimming fuse, LT PARK fuse, and to the RT PARK fuse. From these fuses, current flows to the park lamps, license lamps, side marker lamps, and tail lamps. The front park lamps and side marker lamps are grounded at G104. The tail lamps and rear sidemarker lamps are grounded at G401 and G402. The LIC/dimming fuse supplies battery positive voltage to the license lamps and IPM instrument panel lamp fuse supply voltage circuit for interior lamps dimming. The license lamps are grounded at G402. The inadvertent power control feature prevents the park lamps from remaining on more than 10 minutes if left ON. If the park lamps are turned ON after the ignition switch has been turned OFF, or is in the ACCY position, they will remain ON until turned OFF or the battery runs dead.

Position Lamps - European

The position lamps are on export vehicles only. European countries require that side position lamps are activated when the vehicle is parked along the side of the road. This feature utilizes the front and rear park and the side marker lamps. The position lamp function operates only when the key is in the OFF position and the gear selector is in the PARK position. The position lamp function will operate when the turn signal switch is placed in the right turn position for the right side position lamps to illuminate or the left turn position for the left side position lamps to illuminate. Battery positive voltage is supplied to the standing lamp relay coil and switch. Battery positive voltage is supplied through the normally closed relay contacts of the standing lamp relay switch to each position lamp relay coil. Battery positive voltage is supplied to each position lamp relay switch. When the driver places the turn signal lever in the right or left turn position, the turn signal switch grounds the respective position lamp relay control circuit. This energizes the relay coil, closing the switch contacts providing battery voltage to the respective park and side marker lamps. When the gear selector is out of the PARK position, the rear integration module (RIM) grounds the standing lamp relay coil which removes battery positive voltage from each position lamp relay coil.

Stop Lamps

The brake pedal position (BPP) sensor is used to sense the action of the driver application of the brake pedal. The BPP sensor provides an analog voltage signal that will increase as the brake pedal is applied. The instrument panel module (IPM) provides a low reference signal and a 5-volt reference voltage to the BPP sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the IPM will apply battery voltage to the center high mounted stop lamp (CHMSL), transmission control module (TCM), engine control module (ECM), and stop lamp relay. When the stop lamp relay receives battery voltage from the IPM, the relay coil is energized and the stop lamp relay switch contacts close applying battery voltage through the stop lamps fuse to illuminate the stop lamps. Ground for the left stop lamp and CHMSL is provided at G402 and the right stop lamp is grounded at G401. The stop lamps consist of red lenses and light emitting diodes (LED) instead of incandescent bulbs. The stop lamps on this vehicle will not illuminate unless the ignition is in the accessory, run, or crank positions. When the ignition is in the OFF position, the stop lamps will not illuminate when the brake pedal is applied.

Turn Signal Lamps

With the ignition switch in the RUN position, the turn signal lamps will illuminate when the driver places the turn signal switch in the right or left positions. The instrument panel module (IPM) monitors the signal circuit of the turn signal/multifunction switch. The IPM relays the turn signal switch status to the rear integration module (RIM) via the GMLAN serial data circuit. The RIM uses the status of the turn signal switch to command the turn signals ON and OFF. The RIM controls both front and rear turn signals. The IPM also sends a message via GMLAN to the instrument panel cluster (IPC) to enable the turn signal indicators located in the IPC ON and OFF depending on the position of the turn signal switch. Voltage is supplied to the front and rear turn signals by the RIM. Ground is provided to the front turn signals at G104. The rear turn signals are grounded at G401 and G402. The turn signal/multifunction switch is grounded at G200. The rear turn signal functions are performed by the quarter mounted tail lamps. The rear turn signal lamps consist of red lenses and light emitting diodes (LED) instead of incandescent bulbs.

Hazard Flasher Lamps

The hazard flashers may be activated in any power mode. The instrument panel module (IPM) monitors the signal circuit of the hazard switch. When the hazard switch is placed in the ON position, the switch contacts close and battery positive voltage from the IPM flows through the hazard switch to G201. The rear integration module (RIM) turn lamp supply voltage circuit is also provided with ground through the hazard switch when the contacts close at G201 which in turn illuminates the hazard switch LED. The RIM uses the status of the hazard switch to command the turn signals ON and OFF. The RIM controls both front and rear turn signals. The IPM sends a message via GMLAN to the instrument panel cluster (IPC) to enable both turn signal indicators in an ON and OFF duty cycle when the hazard switch is placed in the ON position. Voltage is supplied to the front and rear turn signals by the RIM. Ground is provided to the front turn signals at G104. The rear turn signals are grounded at G401 and G402.

Repeater Lamps

The repeater lamps are located on the side of the front fender. The repeater lamps are used as additional turn signal lamps, and operate as described in the Turn Signal Lamps description. The repeater lamps are hard wired to there respective front turn signals and receive ground at G104.

Backup Lamps

The left rear fuse block supplies battery positive voltage through the REVERSE LAMP fuse to the coil and switch terminals of the reverse lamp relay. The instrument panel module (IPM) sends a power mode message to the rear integration module (RIM) indicating that the ignition is in the RUN position. When the driver places the gear selector in the REVERSE position, the powertrain control module (PCM) sends a message via GMLAN serial data to the RIM. The RIM provides ground to the reverse lamp relay control circuit which energizes the reverse lamp relay coil. With the reverse lamp relay coil energized, the relay switch contacts close and allow battery positive voltage to flow from the REVERSE LAMP fuse through the relay switch to illuminate the backup lamps. The backup lamps are permanently grounded at G402.

Battery Run Down Protection/Inadvertent Power

To provide battery run down protection, the exterior lamps will be deactivated automatically under certain conditions. The instrument panel module (IPM) monitors the state of the turn signal/multifunction switch. If the park or headlamp switch is ON when the ignition switch is placed in either the CRANK or RUN position and then placed in the OFF position, the IPM initiates a 10-minute timer. At the end of the 10 minutes, the IPM will turn OFF the control power output to the park and headlamp relay coils, deactivating the exterior lamps. This feature will be cancelled if any power mode other than OFF becomes active. The IPM will disable battery run down protection if any of the following conditions exist. The park or headlamp switch is placed in the ON to OFF position, and back to the ON position during battery run down protection. The IPM determined that the park or headlamp switch was not active when the ignition was turned OFF.

Interior Lamps

The interior lamps consist of 2 groups. The first group are those lamps which may not be dimmed. The second group include lamps that may be dimmed.

Courtesy/Illuminated Entry Lamps

Courtesy/illuminated entry lamps are lamps that may be illuminated by opening a door, manually operating a switch or through a remote control door lock receiver (RCDLR) command. This group consist of the following lamps

1. Door courtesy lamps
2. Footwell lamps
3. Illuminated entry lamps
4. Instrument panel (I/P) compartment lamps
5. Overhead console courtesy/reading lamps
6. Rear compartment lamps
7. Vanity mirror lamps

The rear integration module (RIM) controls battery positive voltage and ground to the interior courtesy lamps in the following manner. Battery positive voltage is supplied through the INTERIOR LAMP fuse to both the switch side and coil side of the interior lamp relay. The RIM provides a ground to the control circuit of the interior lamp relay during all power modes except when battery run down protection is active. With the interior lamp relay energized, battery positive voltage is supplied to all the interior lamps in this group. The ground side circuits of the door, footwell, and overhead courtesy lamps are controlled by a pulse width modulated (PWM) ground circuit of the RIM. The RIM pulses the on time of the ground circuit between 0-100 percent at a frequency of approximately 100 hertz. By decreasing the on time percentage of the controlled ground circuit the intensity of the lamps will decrease. This effect is called theater dimming. The RIM will illuminate these lamps under various conditions which will be described in the following information

Courtesy/Illuminated Entry

Courtesy/illuminated entry occurs when any of the door control modules receive a discrete input from the door open switch located in the door latch assembly. The appropriate door control module sends a GMLAN serial data message to the RIM indicating a door is opened. If the ambient light sensor status is dark, the RIM will illuminate the courtesy lamps. The lamps will remain illuminated for 25 seconds after all the doors are closed or until the ignition is placed in the ON position. At this time the RIM will fade the lamps from full intensity to OFF in 3-5 seconds by activating the theater dim feature.

Exit Lighting

Exit lighting is activated when the following conditions exists. The RIM receives a GMLAN serial data message from the instrument panel cluster (IPC) indicating that the ignition key has been removed from the lock cylinder, the ambient light sensor status is dark and all the doors are closed. At this time the RIM will illuminate the interior lamps. During this exit lighting feature, the RIM will also request that the driver door module (DDM) illuminate the driver door switch back lighting at full intensity. The RIM will theater dim the interior lamps after 20-25 seconds. If the key is place back into the lock cylinder before the lamps have dimmed, the RIM will immediately activate the theater dim feature.

Keyless Entry Illumination

Keyless entry illumination is activated when the RCDLR detects a door UNLOCK command from the keyless entry transmitter. The RCDLR will send a GMLAN serial data message to the RIM indicating an UNLOCK command was received. The RIM will activate the courtesy lamps if all the doors are closed, the ignition is in the OFF position, and the ambient light sensor status is dark. The RIM will also send a GMLAN serial data message to the DDM requesting the driver door switches to be illuminated at full intensity. The RIM will keep the lamps illuminated 36-40 seconds and then turn them OFF through the theater dimming feature. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either to the ON or RUN positions the courtesy lamps will deactivate immediately.

Manual Interior Lighting

The interior lamps may also be illuminated manually in all ambient light conditions. When a vehicle occupant places the driver information center (DIC)/dimmer switch to the interior lamp ON position, the contacts in the switch close grounding the interior lamp input circuit of the instrument panel module (IPM). With this input grounded, the IPM sends a GMLAN serial data message to the RIM requesting the interior lamps illuminate. The RIM will ground the lamps as mentioned above. When the I/P dimmer switch is placed out of the interior lamp ON position, the RIM will immediately turn OFF the interior lamps.

Panic Illumination

If the RCDLR detects a panic signal from keyless entry transmitter, the RIM will activate the interior lamps and request the DDM to illuminate the driver door switch back lighting at full intensity. The interior lamps will remain illuminated for 30 seconds or until the RCDLR detects a door UNLOCK message. At this time the RIM will active the theater dim feature.

Reading Lamps

The reading lamps will operate in all ambient light conditions. The reading lamp switches are located in the courtesy/overhead reading lamp assemblies. By pressing the overhead reading lamp switch the contacts in the switch close and provides a direct path to ground for the corresponding reading lamp. When the switch is pressed again, the contacts open turning OFF the reading lamp.

Rear Compartment Lamp

The rear compartment lamp will operate in all ambient light conditions. When the rear deck lid opens, the rear compartment lamp switch in the latch assembly closes to provide a direct path to ground for the rear compartment lamp. Closing the deck lid opens the contacts in the switch turning OFF the rear compartment lamp.

Supplemental Inflatable Restraint (SIR) Lighting

The RIM will provide interior lamp illumination in the event that an air bag has been deployed. Upon deployment of the air bag, the sensing and diagnostic module (SDM) will send a GMLAN serial data message to the RIM. The RIM will activate the interior lamps approximately 15 seconds after the air bag deployment if the ambient light sensor status is dark and the ignition is in the ON position. The interior lamps will remain illuminated until there is a change in the power mode.

Vanity Mirror Lamps

The vanity mirror lamps operate in all ambient light conditions. When the cover on the sunshade is opened, a switch internal to the sun shade closes to provide a direct path to ground. Closing the cover opens the contacts and turns OFF the vanity lamps.

Interior Lamp Dimming

Interior lamp dimming are lamps that may be dimmed by operating the driver information center (DIC)/dimmer switch. This group consist of the following lamps

1. Ashtray lamp
2. Door switches
3. DIC dimmer switch
4. Hazard warning switch
5. Heated seat switches
6. HVAC control head assembly
7. Ignition mode switch
8. Instrument panel cluster (IPC)
9. Memory seat switches
10. Power window switches
11. Radio
12. Rear climate control panel
13. Steering wheel controls
14. Sunroof control switch
15. Traction control switch
16. Transmission shift indicator lamp
17. Trunk release switch

When the park lamp switch is in the ON position, the instrument panel module (IPM) energizes the park lamp relay. With the park lamp relay energized, battery positive voltage is supplied through the DIMMING fuse to the instrument panel lamp fuse supply voltage circuit of the IPM. Upon receiving this voltage supply the IPM requests the status of the ambient light sensor from the climate control panel (CCP). The CCP sends a GMLAN serial data message indicating a Light or Dark status of the ambient light sensor. The IPM will default to dark if the message is not received. If the status of the ambient light sensor is light, then the interior back lighting will not be activated. The IPM also receives an input from the instrument panel (I/P) dimmer switch. The IPM provides the I/P dimmer switch with a 5-volt reference voltage and ground. The I/P dimmer switch is a potentiometer that varies the input signal voltage to the IPM between 0.36-4.23 volts. This input determines the intensity level of the back lighting illumination. The driver may change intensity of the back lighting by positioning the I/P dimmer switch between the minimum and maximum settings. The IPM will default to full intensity if the input from the I/P dimmer switch is not within the specified values. Upon receipt of all the fore mentioned information, the IPM sends a GMLAN serial data message to the CCP, IPC, radio, and all the door modules indicating the ON/OFF status and intensity level of the back lighting. The CCP, IPC, and radio incorporate vacuum fluorescent (VF) lamps that are illuminated at full intensity with the ignition in the ON position. The CCP, IPC, and radio will adjust the VF lamp intensity as requested by the IPM by varying the pulse width modulation of the power feed circuit to the VF lamps. When the door control modules receive the GMLAN serial data message, each door module will supply pulse width modulation (PWM) voltage to the door switch LEDs at the requested intensity. The IPM also supplies voltage to all the remaining lamps at the proper PWM voltage to achieve the requested intensity. The PRNDL incorporates LED lamps that are illuminated at full intensity with the ignition in the ON position. When the park lamps are active, the IPC will adjust the PRNDL LED intensity as requested by the IPM by varying the pulse width modulation of the LED dimming signal circuit to the lamps. All interior back lighting lamps are permanently grounded.

To provide battery run down protection, the interior lamps will be deactivated automatically under certain conditions. The rear integration module (RIM) initiates a 10-minute timer if the interior lamp relay control output is still active, and the ignition switch is in the OFF position. The RIM timer is set to 3 minutes until the vehicle mileage is above 22.5 km (14 mi). At the end of the designated time, the RIM will deactivate the interior lamp relay, disabling the interior lamps. This feature will be cancelled if any power mode other than OFF becomes active. The RIM will reset the timer if any interior lamp switch is turned ON, a door is opened, or the remote control door lock receiver (RCDLR) module is activated.

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Sun Load Temperature Sensor Replacement
• Checking Aftermarket Accessories
• Relay Replacement (Attached to Wire Harness)
• Release Systems Schematics
• Sunshade Replacement
• Symptoms - Hydraulic Brakes
• Turn Signal Multifunction Switch Replacement
• Inside Rearview Mirror Schematics
• Electronic Traction Control Switch Replacement
• Radio Replacement
• Sunroof Switch Replacement
• Automatic Transmission Control Indicator Replacement
• Steering Wheel Control Switch Assembly Replacement
• Instrument Cluster Schematics
• Instrument Panel Insulator Panel Replacement - Left Side
• Fastener Caution
• Defroster Grille Replacement
• Front Bumper Fascia Replacement
• Halogen Bulb Warning
• Lifting and Jacking the Vehicle
• Tire and Wheel Removal and Installation
• Front Wheelhouse Liner Replacement
• Exterior Trim Emblem Removal Caution
• Rear Spoiler Replacement (STS-V)
• DTC B1010
• Brake Pedal Position Sensor Calibration
• Front Fog Lamps Malfunction
• Rear Fog Lamps Malfunction
• Hazard Lamps Malfunction
• Park, License, and/or Tail Lamps Malfunction
• Stop Lamps Malfunction
• Courtesy Lamp Switch Malfunction
• Door Open Switch Malfunction
• Front Fog Lamp Switch Malfunction
• Rear Fog Lamp Switch Malfunction
• Headlamp Switch Malfunction
• Headlamp Leveling Actuator Malfunction
• Suspension Position Sensor Malfunction - Front
• Suspension Position Sensor Malfunction - Rear
• Dimmer Switch Malfunction
• Interior Backlighting Malfunction - Incandescent
• Park Lamp Switch Malfunction
• Brake Pedal Position Sensor (BPPS) Malfunction
• Turn Signal Switch Malfunction
• Turn Signal Indicators Malfunction
• Tail Lamp Outage Detection Malfunction
• Fog Lamp Aiming