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Contents Wiring diagrams Section: Exterior Lights All sections

Lighting System Chevrolet Impala IX

Exterior Lights 32 illustrations ~23275 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Brake Pedal Position Sensor Bolt2 N.m18 lb in
Fog Lamp Nuts2.5 N.m22 lb in
Headlamp Bolts2 N.m18 lb in
High Mounted Stop Lamp Bolts2 N.m18 lb in
HVAC Control Screws2.5 N.m22 lb in
License Lamp Screws2 N.m18 lb in
Tail Lamp Screws2 N.m18 lb in

Scheme 1

Scheme 1: Headlights/Daytime Running Lights (DRL) Wiring Schematics
Scheme 1: Headlights/Daytime Running Lights (DRL) Wiring Schematics

Scheme 2

Scheme 2
Scheme 2

Scheme 3

Scheme 3
Scheme 3

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5: Fog Lights Wiring Schematics
Scheme 5: Fog Lights Wiring Schematics

Scheme 6

Scheme 6: Exterior Lights Wiring Schematics
Scheme 6: Exterior Lights Wiring Schematics

Scheme 7

Scheme 7
Scheme 7

Scheme 8

Scheme 8
Scheme 8

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12: Interior Lights Wiring Schematics
Scheme 12: Interior Lights Wiring Schematics

Scheme 13

Scheme 13
Scheme 13

Scheme 14

Scheme 14: Interior Lights Dimming Wiring Schematics
Scheme 14: Interior Lights Dimming Wiring Schematics

Scheme 15

Scheme 15
Scheme 15

DIAGNOSTIC CODE INDEX

DTCDescription
DTC B1395B1395 03: Device Voltage Output 1 Circuit Voltage Below Threshold B1395 07: Device Voltage Output 1 Circuit Voltage Above Threshold
DTC B2530B2530 00: Front Fog Lamp Control Circuit
DTC B2545B2545 00: Backup Lamps Circuit
DTC B2575B2575 00: Headlamp Control Circuit
DTC B257AB257A 00: Headlamp Switch Input Signal Mismatch
DTC B2580B2580 00: Headlamp High Beam Control Circuit
DTC B2585B2585 00: Park Lamp Control Circuit
DTC B2600B2600 00: Daytime Running Lamp Control Circuit
DTC B261AB261A 00: Passenger Compartment Dimming 4 Circuit Short to Ground
DTC B2610B2610 00: Passenger Compartment Dimming 1 Circuit
DTC B2615B2615 00: Passenger Compartment Dimming 2 Circuit
DTC B2625B2625 00: Display Dimming Pulse Width Modulation (PWM) Output Circuit
DTC B2645B2645 03: Ambient Light Sensor Circuit Voltage Below Threshold B2645 07: Ambient Light Sensor Circuit Voltage Above Threshold
DTC B2652B2652 00: Passenger Compartment Dimming 3 Circuit
DTC B3445 or B3884B3445 00: Stop Lamp Circuit B3884 00: Center High Mounted Stop Lamp (CHMSL) Circuit
DTC B3600B3600 03: Passenger Compartment Dimming Request Signal Circuit Voltage Below Threshold
DTC C0277 or C0890C0277 06: Brake Pedal Position Sensor Circuit Short to Ground or Open C0277 07: Brake Pedal Position Sensor Circuit Voltage Above Threshold C0277 09: Brake Pedal Position Sensor Circuit Rate of Change Above Threshold C0277 4B: Brake Pedal Position Sensor Calibration Not Learned C0890 03: Device Voltage Reference Output 3 Circuit Voltage Below Threshold C0890 07: Device Voltage Reference Output 3 Circuit Voltage Above Threshold
DTC C0297C0297 00: Brake Applied Output Circuit

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ Terminal 3 X3B1395 03, B3600 03B1395 03, B3600 03
I/P Dimmer Switch B+ Voltage ReferenceB1395 03, B3600 03B3600 03B1395 07
I/P Dimmer Switch SignalB3600 03B3600 031
1. Interior Backlighting Malfunction

Circuit/System Description

The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies a pulse width modulated (PWM) voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

B1395 03

The DTC will set for the following conditions

  1. The BCM detects a short to ground in the I/P dimmer switch voltage reference circuit.
  2. The BCM detects a short to ground or an open/high resistance in the INT LTS/PNL DIM fuse B+ circuit.

B1395 07

The DTC will set when the BCM detects a short to voltage in the I/P dimming voltage reference circuit or the vehicles system voltage exceeds the normal operating range of 16 volts.

Actions Taken When the DTC Sets

  1. The I/P dimmer switch will not operate.
  2. The I/P dimming lamps will not illuminate.

Conditions for Clearing the DTC

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Dimming Control Reference voltage. The reading should display 2.5 volts or greater.

  1. If less than the specified range, refer to I/P Dimming Control Malfunction.
  2. If within the specified range, refer to I/P Dimmer Switch Malfunction.

Circuit/System Testing

I/P Dimmer Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, test for B+ between the voltage reference circuit terminal 15 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool Dimming Control Signal parameter is greater than 2.5 volts. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the headlamp switch.

I/P Dimming Control Malfunction

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. If all circuit tests normal, replace the BCM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Fog Lamp Switch Signal222
Fog Lamp Relay Control11B2530 00
Fog Lamp Control111
Fog Lamp - LF Ground1
Fog Lamp - RF Ground1
Headlamp Switch Ground2
1. Front Fog Lamps Malfunction 2. Front Fog Lamp Switch Malfunction

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

  1. Battery voltage must be between 9-16 volts.
  2. Fog lamps ON.

Conditions for Setting the DTC

The BCM detects a short to voltage in the fog lamp relay control circuit.

When the DTC is present, the fog lamps will not operate when the park lamps are ON and the front fog lamp switch is active.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal H5.
  3. Command the Fog 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 BCM. 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 BCM.
  4. If all circuits test normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ Terminal 2 X2B2545 00, B2652 00B2652 00
Body Control Module (BCM) B+ Terminal 4 X4B2545 00, B2652 00B2545 00
Backup Lamps ControlB2545 0011
Backup Lamp - Left Ground1
Backup Lamp - Right Ground1
1. Backup Lamps Malfunction

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies battery voltage to the backup lamps and inside rearview mirror. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the backup lamp control circuit. The engine may need to be running for the backup lamps to function.

Battery voltage must be between 9-16 V.

DTC B2545 00 will set when one of the following conditions exits

  1. The BCM detects a short to ground in the backup lamps control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the BCM B+ circuit terminal 4 X4.

When the DTC is present, the backup lamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

With DD6

  1. Ignition OFF, disconnect the X2 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X2 harness connector at the BCM.
  4. Disconnect the X4 harness connector at the BCM.
  5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. Ignition OFF, connect the X4 harness connector at the BCM.
  7. Disconnect the harness connector at the inside rearview mirror.
  8. Connect a test lamp between the control circuit terminal 9 and ground.
  9. 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 voltage. If the circuit tests normal, replace the BCM. 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 BCM.
  10. Ignition OFF, connect the harness connector at the inside rearview mirror.
  11. Disconnect the harness connector at the inoperative backup lamp.
  12. 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.
  13. Connect a test lamp between the control circuit terminal A and ground.
  14. 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 voltage. If the circuit tests normal, replace the BCM. 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 BCM.
  15. If all circuits test normal, test or replace the inoperative backup lamp.

Without DD6

  1. Ignition OFF, disconnect the X2 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X2 harness connector at the BCM.
  4. Disconnect the X4 harness connector at the BCM.
  5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. Ignition OFF, connect the X4 harness connector at the BCM.
  7. Disconnect the harness connector at the inoperative backup lamp.
  8. 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.
  9. Connect a test lamp between the control circuit terminal A and ground.
  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 voltage. If the circuit tests normal, replace the BCM. 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 BCM.
  11. If all circuits test normal, test or replace the inoperative backup lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Backup Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Inside Rearview Mirror Replacement»(/chevrolet/impala/ix-2006-2016/remont/mirrors/#mirror-system)
  3. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal111
Headlamp Switch High Beam Signal111
Headlamp Switch Headlamps ON SignalB257A 001B257A 00
Headlamp Switch Headlamps OFF SignalB257A 001B257A 00
Park Lamp Switch Park Lamps ON SignalB257A 00B257A 00B257A 00
Headlamp High Beam Relay Control11B2580 00
Headlamp Low Beam Relay Control11B2575 00
LF High Beam Headlamp Control111
LF Low Beam Headlamp Control111
RF High Beam Headlamp Control111
RF Low Beam Headlamp Control111
LF Headlamp Ground1
RF Headlamp Ground1
Headlamp Switch Ground1
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction

When the headlamp switch is placed in the headlamp position, ground is applied to the body control module (BCM) through the headlamp low beam signal circuit. The BCM then applies ground to the headlamp low beam relay control circuit which energizes the low beam relay. With the low beam relay energized, the switch contacts close allowing battery voltage to flow through the LO BEAM fuses to the low beam headlamps.

  1. Battery voltage must be between 9-16 volts.
  2. Headlamps ON.

The BCM detects a short to voltage in the headlamp low beam relay control circuit.

Action Taken When the DTC Sets

The low beam headlamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal A5.
  3. Command the Low Beams 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 BCM. 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 BCM.
  4. If all circuits test normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal111
Headlamp Switch High Beam Signal111
Headlamp Switch Headlamps ON SignalB257A 001B257A 00
Headlamp Switch Headlamps OFF SignalB257A 001B257A 00
Park Lamp Switch Park Lamps ON SignalB257A 00B257A 00B257A 00
Headlamp High Beam Relay Control11B2580 00
Headlamp Low Beam Relay Control11B2575 00
LF High Beam Headlamp Control111
LF Low Beam Headlamp Control111
RF High Beam Headlamp Control111
RF Low Beam Headlamp Control111
LF Headlamp Ground1
RF Headlamp Ground1
Headlamp Switch Ground1
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction

When the headlamp switch is placed in the AUTO position, the body control module (BCM) receives a ground signal through the headlamp switch headlamps OFF signal circuit. The headlamp switch headlamps ON signal circuit and the park lamp switch signal circuit are both open and have no ground signal. When the headlamp switch is placed in the PARK or HEAD position, the BCM will receive a ground signal through the headlamp switch headlamps ON signal circuit and the park lamp switch signal circuit. The headlamp switch headlamps OFF signal circuit will be open and have no ground signal

Battery voltage must be between 9-16 volts.

The BCM receives a mismatched signal between the headlamps OFF signal circuit, the headlamp switch headlamps ON signal circuit, and the park lamp switch ON signal circuit.

The BCM disregards the headlamp switch input and defaults to automatic headlamp function.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition ON, test for B+ between the signal circuits listed below and ground. Headlamps ON signal terminal 1 Park lamp ON signal terminal 2 Headlamp OFF signal terminal 3 If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Parklamp 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 BCM.
  4. If all circuits test normal, test or replace the headlamp switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal111
Headlamp Switch High Beam Signal111
Headlamp Switch Headlamps ON SignalB257A 001B257A 00
Headlamp Switch Headlamps OFF SignalB257A 001B257A 00
Park Lamp Switch Park Lamps ON SignalB257A 00B257A 00B257A 00
Headlamp High Beam Relay Control11B2580 00
Headlamp Low Beam Relay Control11B2575 00
LF High Beam Headlamp Control111
LF Low Beam Headlamp Control111
RF High Beam Headlamp Control111
RF Low Beam Headlamp Control111
LF Headlamp Ground1
RF Headlamp Ground1
Headlamp Switch Ground1
Turn Signal/Multifunction Switch Ground1
1. Headlamps Malfunction

When the turn signal/multifunction switch is placed in the headlamps high or flash to pass (FTP) position, ground is applied to the body control module (BCM) through the headlamp high beam signal circuit or the flash to pass switch signal circuit. The BCM applies ground to the headlamp high beam relay control circuit which energizes the high beam relay. With the high beam relay energized, the switch contacts close allowing battery voltage to flow through the HI BEAM fuses to the high beam headlamps.

  1. Battery voltage must be between 9-16 volts.
  2. Headlamps ON.

The BCM detects a short to voltage in the headlamp high beam relay control circuit.

The high beam headlamps and flash to pass (FTP) will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal C6.
  3. Command the High Beams 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 BCM. 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 BCM.
  4. If the circuit tests normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamps ON SignalB257A 00B257A 00B257A 00
Park Lamp Relay Control11B2585 00
License Lamp Control111
Park Lamp Control111
License Lamp Ground1
Park Lamps - LF Ground1
Park Lamps - RF Ground1
Tail/Stop and Turn Signal Lamps - LR Ground1
Tail/Stop and Turn Signal Lamps - RR Ground1
Headlamp Switch Ground1
1. Park, License, and/or Tail Lamps Malfunction

Battery positive voltage is applied at all times to both the coil and switched sides of the PARK LP Relay. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow through the LT PARK and RT PARK fuses to all of the park, tail, license, and marker lamps.

  1. Battery voltage must be between 9-16 volts.
  2. Park lamps ON.

The BCM detect a short to voltage in the park lamp relay control circuit.

The park lamps will not operate.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal K2.
  3. Command the Parking 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 BCM. 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 BCM.
  4. If all circuits test normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
DRL Relay Control22B2600 00
DRL Control222
LF Low Beam Headlamp Control111
RF Low Beam Headlamp Control111
Ambient Light Sensor GroundB2645 07
LF Headlamp Ground1
RF Headlamp Ground1
1. Headlamps Malfunction 2. Daytime Running Lamps Malfunction

Circuit Description

The ambient light sensor is a light sensitive transistor that varies the voltage signal to the body control module (BCM) based on outside lighting conditions. When the ambient light sensor indicates daytime conditions, the body control module (BCM) grounds the DRL relay control circuit energizing the DRL relay. With the DRL relay energized, the switch contacts close and voltage is applied to the DRL 1 and DRL 2 fuses to the left and right low beam headlamps. Any function or condition that turns on the headlamps will cancel DRL operation.

Conditions for Running the DTCs

Battery voltage must be between 9-16 volts.

The BCM detect a short to voltage in the DRL relay control circuit.

The BCM will deactivate the DRL relay for the remainder of the ignition cycle.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X4 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal H2.
  3. Command the DRL 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 BCM. 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 BCM.
  4. If all circuits test normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Accent Lamp ControlB261A 0021
Accent Lamp Ground2
1. Interior Accent Lighting Always ON 2. Interior Accent Lighting Always OFF

The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the light are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the individual accent lamps via the accent lamps control circuit.

  1. Battery voltage must be between 9-16 V.
  2. Park lamps ON.

The BCM detects a short to ground in the accent lamp control circuit.

The BCM will not illuminate the accent lamps supplied by the accent lamp control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Note. Each back lighted component may need to be disconnected to isolate a short to voltage or short to ground. Use the schematic to identify the following: Back lighted components the vehicle is equipped with. Component locations on the back lighting dimming control circuit. Each components control and ground circuit terminals.

  1. Ignition OFF, disconnect the harness connector at any component with inoperative backlighting.
  2. Ignition OFF, scan tool disconnected, interior lamps OFF, doors CLOSED, test for less than 5 ohms between the ground circuit and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit and ground.
  4. 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 BCM. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  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.

Control Module References for control module replacement, setup, and programming

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
LED Dimming ControlB2610 0011
1. Interior Backlighting Malfunction

The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the LED dimming supply circuit illuminating the components listed below

  1. Radio
  2. HVAC control module
  3. Driver information center (DIC) switch
  4. Steering wheel controls
  1. Battery voltage must be between 9-16 volts.
  2. Park lamps ON.

The BCM detects a short to ground on the LED dimming control circuit.

The BCM does not attempt to illuminate the LED lamps.

  1. The condition for setting the DTC is no longer present.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connectors at all components fed by the control circuit terminal 18 X3.
  2. Ignition ON, clear the DTC with a scan tool.
  3. Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset. If the DTC resets, test the control circuit for a short to ground. If the circuit test normal, replace the BCM.
  4. Reconnect each component one at a time and verify that the DTC does not reset as current. If the DTC resets as current, test or replace the component responsible for setting the DTC.
  5. If all circuits and components test normal, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Driver Information Display Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
  2. «Steering Wheel Control Switch Assembly Replacement»(/chevrolet/impala/ix-2006-2016/remont/memory-modules/#secondary-and-configurable-customer-control-system)
  3. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, HVAC control module, and radio replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ terminal 2 X4B2615 00B2615 00
Courtesy Lamps ControlB2615 0011
1. Courtesy Lamps Malfunction

Battery voltage for the courtesy lamps is supplied at all times, from the INT LIGHTS Fuse located in the underhood fuse block, to the body control module (BCM). When the BCM receives a signal to command the courtesy lamps ON, it applies voltage through the courtesy lamps supply voltage circuits to the courtesy lamps listed below.

  1. The left and right I/P courtesy lamps
  2. Dome lamp
  3. Right front turn signal

Battery voltage must be between 9-16 volts.

DTC B2615 00 will set for the following conditions

  1. The BCM detects a short to ground in the courtesy lamps control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the INT LIGHTS fuse B+ circuit terminal 2 X4.

The BCM will not illuminate any courtesy lamps supplied by the courtesy lamps control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X4 harness connector at the BCM.
  4. Disconnect the harness connectors at the following components. Left I/P Courtesy Lamp Right I/P Courtesy Lamp Dome Lamp - Coupe Dome/Reading Lamp - Sedan
  5. Ignition ON, clear the DTC with a scan tool.
  6. Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset. If the DTC resets, test the control circuits for a short to ground. If the circuits test normal, replace the BCM.
  7. Reconnect each component one at a time and verify that the DTC does not reset. If the DTC resets, test or replace the component responsible for setting the DTC.
  8. If all circuits and components test normal, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Dome Lamp Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Instrument Panel Courtesy Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
LED Dimming SupplyB2625 0021
1. Interior Backlighting Does Not Dim 2. Interior Backlighting Does Not Dim

The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal then applies a pulse width modulated (PWM) voltage through the LED dimming supply circuit illuminating the HVAC control module to the requested level.

  1. Ignition ON.
  2. Park Lamps ON.

The BCM detects a short to ground on the LED dimming supply circuit.

The BCM will not attempt to illuminate the LED indicator lamps control circuit.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, cover the ambient light sensor, vary the interior lamp dimming switch from dim to full bright. The LED lamps should dim and then become full bright.

  1. Ignition OFF, disconnect the harness connectors at all components fed by the LED backlight dimming supply circuit terminal 18 X3.
  2. Ignition ON, clear the DTC with a scan tool.
  3. Operate the vehicle within the conditions for running the DTC and verify the DTC does not reset. If the DTC resets, test the LED dimming supply circuit for a short to ground. If the circuit test normal, replace the BCM.
  4. Reconnect each component one at a time and verify the DTC does not reset as current. If the DTC resets as current, test or replace the component responsible for setting the DTC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Radio Replacement»(/chevrolet/impala/ix-2006-2016/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  2. «Driver Information Display Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
  3. «Steering Wheel Control Switch Assembly Replacement»(/chevrolet/impala/ix-2006-2016/remont/memory-modules/#secondary-and-configurable-customer-control-system)
  4. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or HVAC control module replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
Ambient Light Sensor GroundB2645 07

The ambient light sensor is used to monitor outside lighting conditions. The body control module (BCM) provides a 5-volt reference signal to the ambient light sensor. The sensor is a variable resistor, it's resistance changes as outside lighting conditions change. With the headlamp switch in the AUTO position, the BCM monitors the sensor signal circuit to determine if the outside lighting conditions are correct for either daytime running lamps (DRL) or headlamp low beam operation. In daylight conditions, the BCM will command the DRLs ON. In low light conditions, the BCM will command the low beam headlamps ON.

Battery voltage must be between 9-16 volts.

B2645 03

The DTC will set when the BCM detects a short to ground in the ambient light sensor signal circuit.

B2645 07

The DTC will set when the BCM detects a short to voltage or an open/high resistance in the ambient light sensor signal circuit.

  1. Automatic lamp control (ALC) is inoperative.
  2. The BCM defaults to low light status and commands the low beam headlamps ON.
  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the ambient light sensor.
  2. Ignition 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. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 volts. If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and the ground circuit terminal B. Verify the scan tool Ambient Light Sensor parameter is less than 1.96 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 BCM.
  5. If all circuits test normal, test or replace the ambient light sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Daytime Running Lamp (DRL) Ambient Light Sensor Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ Terminal 2 X2B2545 00, B2652 00B2652 00
Body Control Module (BCM) B+, Terminal 4 X4B2545 00, B2652 00B2545 00
Instrument Panel Lamps ControlB2652 0011
1. Interior backlighting Malfunction

The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage from the CHMSL/BCK-UP fuse through the instrument panel lamp control circuit and the interior backlighting components dim to the requested level.

  1. Battery voltage must be between 9-16 volts.
  2. Park lamps ON.

DTC B2652 00 will set for the following conditions

  1. The BCM detects a short to ground in the instrument panel lamps control circuit.
  2. The BCM detects a short to ground or an open/high resistance in the BCM B+ circuit terminal 2 X2 or the BCM B+ circuit terminal 4 X4.

The BCM will not DIM or illuminate any I/P lamps supplied by the I/P lamps dimmer switch.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X2 harness connector at the BCM.
  4. Disconnect the X4 harness connector at the BCM.
  5. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 4 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. Ignition OFF, connect the X4 harness connector at the BCM.
  7. Disconnect the harness connectors at the following components. Headlamp Switch Instrument Panel Cluster (IPC) Driver Window Switch Driver Door Lock Switch Outside Rearview Mirror Switch Passenger Window Switch Passenger Door Lock Switch
  8. Ignition ON, clear the DTC with a scan tool.
  9. Operate the system within the Conditions for Running the DTC and verify the DTC does not reset. If the DTC resets, test the control circuits for a short to ground. If the circuits test normal, replace the BCM.
  10. Reconnect each component one at a time and verify that the DTC does not reset as current. If the DTC resets as current, test or replace the component responsible for setting the DTC.
  11. If all circuits test normal, replace the BCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Instrument Cluster Replacement»(/chevrolet/impala/ix-2006-2016/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
  3. «Front Side Door Window Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/heated-glassdefoggers/#fixed-and-moveable-windows)
  4. «Door Lock Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  5. «Power Mirror Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/mirrors/#mirror-system)
  6. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
CHMSL ControlB3445 00, B3884 0011
CHMSL Ground1
1. Center High Mounted Stop Lamp (CHMSL) Malfunction

Battery voltage is applied at all times to the body control module (BCM) from the CHMSL/BCK-UP Fuse located in the underhood fuse block. When the brake pedal is applied and the BCM receives a brake applied signal from the brake pedal position sensor (BPPS). It then applies battery voltage from the CHMSL/BCK-UP fuse through the CHMSL voltage supply circuit to the CHMSL.

  1. Battery voltage must be between 9-16 volts.
  2. Brakes APPLIED.

The BCM detects a short to ground in the CHMSL control circuit when the stop lamps are being commanded ON.

The BCM will not illuminate the CHMSL.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the CHMSL.
  2. Ignition OFF, test for less than 10 ohms between the ground circuit terminal A 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 B and ground.
  4. Ignition ON, press and release the brake pedal. 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 BCM. 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 BCM.
  5. If all circuits test normal, test or replace the CHMSL.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «High Mount Stop Lamp Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03, B3600 03B3600 03B1395 07
Instrument Panel Lamps Dimmer Switch SignalB3600 03B3600 031
1. Interior Backlighting Malfunction

The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the I/P lamps supply voltage circuit and the LED dimming supply circuit to all related interior lamps, illuminating them to the desired level of brightness.

Battery voltage must be between 9-16 volts.

  1. The BCM detects a short to ground or open in the I/P dimming voltage reference circuit.
  2. The BCM detects a short to ground or open in the instrument panel lamps dimming signal circuit.

The I/P lamps are not illuminated.

  1. The condition responsible for setting the DTC no longer exists.
  2. A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition ON, test for B+ between the reference voltage circuit terminal 15 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.
  3. Verify the scan tool Dimming Control Signal parameter is less than 0.2 volts. If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM
  4. Install a 3A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool Dimming Control Signal parameter is greater than 2.75 volts. If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, replace the headlamp switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ Terminal 1 X411
Body Control Module (BCM) B+ Terminal 3 X422
Brake Pedal Position Sensor 5-Volt ReferenceC0277 06, C0890 03C0277 06C0277 06
Brake Applied SignalC0297 0044
Brake Pedal Position Sensor SignalC0277 06C0277 06C0277 07C0277 09, C0277 4B
Center High Mounted Stop Lamp (CHMSL) ControlB3445 00, B3884 0033
Left Rear Stop/Turn Lamp Control111
Right Rear Stop/Turn Lamp Control222
Brake Pedal Position Sensor Low ReferenceC0277 061
Center High Mounted Stop Lamp (CHMSL) Ground3
Left Rear Stop/Turn Lamp Ground1
Right Rear Stop/Turn Lamp Ground2
1. Stop Lamps Malfunction - Left 2. Stop Lamps Malfunction - Right 3. Center High Mounted Stop Lamp (CHMSL) Malfunction 4. Cruise Control Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the stop lamps, center high mounted stop lamp (CHMSL), transmission control module (TCM), and engine control module (ECM).

  1. Battery voltage must be between 9-16 volts.
  2. Brakes APPLIED.

C0277 06

This DTC will set for the following conditions

  1. The BCM detects a short to ground or an open/high resistance in the brake pedal position sensor signal circuit.
  2. The BCM detects a short to ground or an open/high resistance in the brake pedal position sensor 5-volt reference circuit.

C0277 07

This DTC will set for the following conditions

  1. The BCM detects a short to battery voltage in the brake pedal position sensor signal circuit.
  2. The BCM detects a short to battery voltage in the brake pedal position sensor 5-Volt Reference circuit.

C0277 09

The BCM detects the brake pedal position sensor signal is changing faster than possible under normal operating conditions.

C0277 4B

The DTC will set when the brake pedal position sensor home position is not learned.

C0890 03

The BCM detects a short to ground in the brake pedal position sensor voltage reference circuit.

C0890 07

The BCM detects a short to battery voltage in the brake pedal position sensor voltage reference circuits.

  1. The Service Vehicle Soon indicator is commanded ON.
  2. If the DTC sets while the vehicle is running, the BCM 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. For DTC C0277 07 the ignition must be cycled before the code can be cleared.
  3. For DTC C0277 4B a successful brake pedal position sensor calibration has been performed.
  4. A history DTC will clear once 50 malfunction-free ignition cycles have occurred.
  5. DTC will not clear the current status until the next ignition cycle.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  3. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)
  4. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)

Scan Tool Reference

Control Module References for scan tool information

C0277 06, C0277 07, C0890 03, and C0890 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 C. If the test lamp does not illuminate, test the low reference circuit for s short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  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 BCM. If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool BPP Sensor parameter is less than 100 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 BCM.
  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 BPP Sensor parameter is greater than 400 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 BCM.
  6. If all circuits test normal, test or replace the brake pedal position sensor.

C0277 09

  1. Replace the brake pedal position sensor.
  2. Perform the brake pedal position sensor recalibration procedure. Refer to «Brake Pedal Position Sensor Calibration»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) .
  3. Operate the vehicle within the Conditions for Running and Setting the DTC and verify the DTC does not reset. If the DTC resets, replace the BCM.

C0277 4B

  1. Verify that the DTC sets under the Conditions for Running and Setting.
  2. Perform the brake pedal position sensor recalibration procedure. Refer to «Brake Pedal Position Sensor Calibration»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration) .
  3. Operate the vehicle within the Conditions for Running and Setting the DTC and verify the DTC does not reset. 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 Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-replacement)
  2. «Brake Pedal Position Sensor Calibration»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
  3. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ Terminal 1 X411
Body Control Module (BCM) B+ Terminal 3 X422
Brake Pedal Position Sensor 5-Volt ReferenceC0277 06, C0890 03C0277 06C0277 06
Brake Applied SignalC0297 0044
Brake Pedal Position Sensor SignalC0277 06C0277 06C0277 07C0277 09, C0277 4B
Center High Mounted Stop Lamp (CHMSL) ControlB3445 00, B3884 0033
Left Rear Stop/Turn Lamp Control111
Right Rear Stop/Turn Lamp Control222
Brake Pedal Position Sensor Low ReferenceC0277 061
Center High Mounted Stop Lamp (CHMSL) Ground3
Left Rear Stop/Turn Lamp Ground1
Right Rear Stop/Turn Lamp Ground2
1. Stop Lamps Malfunction - Left 2. Stop Lamps Malfunction - Right 3. Center High Mounted Stop Lamp (CHMSL) Malfunction 4. Cruise Control Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5-volt reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery ltage to the stop lamps, center high mounted stop lamp (CHMSL), transmission control module (TCM), and engine control module (ECM).

  1. Battery voltage must be between 9-16 volts.
  2. Brakes APPLIED.

The BCM detects a short to ground in the brake applied signal circuit.

  1. The BCM stores the DTC to memory.
  2. The Service Vehicle Soon indicator is commanded ON.
  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.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X1 harness connector at the ECM.
  2. Connect a test lamp between the appropriate signal circuit terminal listed below and ground. Brake applied signal terminal 7 - with LS4 Brake applied signal terminal 9 - with LZE, LZ4, or LZ8
  3. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit test normal, replace the BCM. If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.
  4. Ignition OFF, connect a test lamp between the appropriate signal circuit terminal listed below at the ECM harness connector and the connector terminal at the ECM. Brake applied signal terminal 7 - with LS4 Brake applied signal terminal 9 - with LZE, LZ4, or LZ8
  5. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp does not turn ON and OFF when commanded, replace the ECM.
  6. Ignition OFF, connect the harness connector at the ECM.
  7. Disconnect the harness connector at the TCM.
  8. Connect a test lamp between the signal circuit terminal 42 and ground.
  9. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit test normal, replace the BCM. If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the BCM.
  10. If all circuits test normal, replace the TCM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM, ECM or TCM replacement, setup and programming

Symptoms - Lighting

Note. The following steps must be completed before doing the Symptom tables.

  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) . No DTCs are set. The control modules can communicate via the serial data link.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following: «Exterior Lighting Systems Description and Operation»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system) «Interior Lighting Systems Description and Operation»(/chevrolet/impala/ix-2006-2016/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»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. 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»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Courtesy Lamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Daytime Running Lamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  4. «Front Fog Lamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  5. «Hazard Lamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  6. «Headlamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  7. «Interior Backlighting Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  8. «Park, License, and/or Tail Lamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  9. «Stop Lamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  10. «Turn Signal Lamps and/or Indicators Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ Terminal 4 X4B2545 00, B2652 00B2545 00
Backup Lamps ControlB2545 0011
Backup Lamp - Left Ground1
Backup Lamp - Right Ground1
1. Backup Lamps Malfunction

When the transmission is placed in the REVERSE position, the transmission control module (TCM) sends a serial data message to the body control module (BCM). The message indicates that the gear selector is in the REVERSE position. The BCM applies battery voltage to the backup lamps and inside rearview mirror. Once the driver moves the gear selector out of the REVERSE position, a message is sent by the TCM via serial data requesting the BCM to remove battery voltage from the backup lamp control circuit. The engine may need to be running for the backup lamps to function.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Command the Backup Lamps ON and OFF with a scan tool. The backup lamps should turn ON and OFF when commanded.

  1. Ignition OFF, disconnect the harness connector at the appropriate backup lamp.
  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 ground.
  4. 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 voltage. If the circuit tests normal, replace the BCM. 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, BCM.
  5. If all circuits test normal, test or replace the backup lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Backup Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Tail Lamp Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Inside Rearview Mirror Replacement»(/chevrolet/impala/ix-2006-2016/remont/mirrors/#mirror-system)
  4. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Instrument Panel Lamps Dimmer Switch SignalB3600 03B3600 032
Left Front Door Open Switch Signal443
Passenger Door Open Switch Signal554
Courtesy Lamp ControlB2615 001
I/P Dimming ControlB1395 007
Inadvertent Power Courtesy Lamp ControlB1480 0061
Dome Lamp Ground1
Door Lock Ground - Driver4
Door Lock Ground - Front Passenger5
Door Lock Ground - LR5
Door Lock Ground - RR5
Inadvertent Courtesy Lamp Ground6
I/P Courtesy Lamp Ground - Left2
I/P Courtesy Lamp Ground - Right2
1. Dome Lamps Malfunction 2. IP Courtesy Lamps Malfunction 3. Dome Lamp Switch Malfunction 4. Door Open Switch Malfunction-Driver 5. Door Open Switch Malfunction-Passenger 6. Inadvertent Power Courtesy Lamps Malfunction 7. Interior Backlighting Malfunction

The INT LIGHTS fuse supplies battery voltage to the body control module (BCM). The BCM applies battery voltage to the courtesy lamps through the courtesy lamp supply voltage circuit. When any door is opened, the door open switch contacts close and the BCM receives a door-open input. If the BCM receives a door lock or unlock input, the BCM will activate the courtesy lamp supply voltage circuit, providing battery voltage to the dome lamp and instrument panel (I/P) courtesy lamps. The courtesy lamps can be manually activated by placing the interior lamp switch in the DOME position. For more detailed information concerning courtesy lamp operation refer to Interior Lighting Systems Description and Operation .

Inadvertent power courtesy lamp feature provides a similar function for the interior lamps as a retained accessory power feature. The BCM will energize the courtesy lamps supply voltage circuit when the BCM is in the active state (awake). When the inadvertent power courtesy lamps supply voltage circuit is energized, it supplies voltage to all the interior lights listed below. The BCM will continue to supply voltage to the interior lamps after the ignition is turned OFF so that the interior lamps may be operated.

  1. Dome/Reading Lamp
  2. Vanity Mirror Lamps
  3. Reading Lamp Assembly
  4. Inside Rearview Mirror
  5. Rear Compartment Courtesy Lamp

In the event that any of these lamps were to remain illuminated for a period of more than 20 minutes with the ignition switch in the OFF position and no BCM input activity, the BCM will deactivate the inadvertent power supply voltage circuit to prevent a total battery discharge condition.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Door Ajar Switch parameter while opening and closing each vehicle door. The parameter should change between Door Ajar and Door Closed. If the parameter does not change between the selected states, refer to «Door Ajar Indicator Malfunction»(/chevrolet/impala/ix-2006-2016/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) .
  2. Observe the scan tool Rear Closure Ajar Sw. parameter while opening and closing the trunk. The parameter should change between Active and Inactive. If the parameter does not change between the selected states, refer to «Trunk Ajar Indicator Malfunction»(/chevrolet/impala/ix-2006-2016/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems) .
  3. Command the Courtesy Lamps ON and OFF with a scan tool. The courtesy lamps should turn ON and OFF when changing between the commanded states. If the courtesy lamps do not turn ON and OFF when commanded, refer to Dome Lamp Malfunction.
  4. Turn the individual reading lamps ON and OFF with their respective switches. The reading lamps should turn ON and OFF when changing between the selected states. If any reading lamp does not turn ON and OFF when selected, refer to Inadvertent Power Courtesy Lamps Malfunction.
  5. Turn the left and right vanity mirror lamps ON and OFF with their respective switches. The vanity mirror lamps should turn ON and OFF when changing between the selected states. If any reading lamp does not turn ON and OFF when selected, refer to Inadvertent Power Courtesy Lamps Malfunction.
  6. Turn the rear compartment courtesy lamp ON and OFF by opening and closing the trunk. The rear compartment courtesy lamp should turn ON and OFF when changing between the selected states. If the rear compartment courtesy lamp does not turn ON and OFF when selected, refer to Inadvertent Power Courtesy Lamps Malfunction.

Dome Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the dome lamp.
  2. Verify that a test lamp illuminates between the ground circuit terminal B and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the control circuit terminal A and ground.
  4. Command the 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 for a short to voltage. If the circuit tests normal, replace the BCM. 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 BCM.
  5. If all circuits test normal, test or replace the dome lamp.

Inadvertent Power Courtesy Lamps Malfunction

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the BCM and disconnect the harness connector at the appropriate courtesy lamp.
  4. Verify that a test lamp illuminates between the appropriate ground circuit terminal listed below and B+. Dome/Reading Lamp - terminal B Left or Right Vanity Mirror - terminal B Reading Lamp Assembly - terminal B Inside Rearview Mirror - terminal 7 (w/o UE1) Inside Rearview Mirror - terminal 8 (with UE1) Rear Compartment Courtesy Lamp - terminal B If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  5. Ignition ON, verify that a test lamp illuminates between the appropriate inadvertent power courtesy lamp circuit terminal listed below and ground. Dome/Reading Lamp - terminal B Left or Right Vanity Mirror - terminal B Reading Lamp Assembly - terminal A Inside Rearview Mirror - terminal 2 (w/o UE1) Inside Rearview Mirror - terminal 6 (with UE1) Rear Compartment Courtesy Lamp - terminal A 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 BCM.
  6. If all circuits test normal, test or replace the courtesy lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Reading Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Instrument Panel Courtesy Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  4. «Sunshade Illuminated Mirror Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  5. «Dome Lamp Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  6. «Dome Lamp Bulb Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  7. «Emergency Vehicle Rear Compartment Lid Lamp Replacement (Impala RPO T53)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  8. «Rear Compartment Lid Lamp Lens and Bulb Replacement (Impala RPO T53)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  9. «Rear Compartment Courtesy Lamp Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  10. «Front Side Door Lock Replacement»(/chevrolet/impala/ix-2006-2016/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  11. «Rear Side Door Lock Replacement»(/chevrolet/impala/ix-2006-2016/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  12. «Inside Rearview Mirror Replacement»(/chevrolet/impala/ix-2006-2016/remont/mirrors/#mirror-system)
  13. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ambient Light Sensor SignalB2645 03B2645 07B2645 07
DRL Relay Control22B2600 00
DRL Control222
LF Low Beam Headlamp Control111
RF Low Beam Headlamp Control111
Ambient Light Sensor GroundB2645 07
LF Headlamp Ground1
RF Headlamp Ground1
1. Headlamps Malfunction 2. Daytime Running Lamps Malfunction

The ambient light sensor is a light sensitive transistor that varies the voltage signal to the body control module (BCM) based on outside lighting conditions. When the ambient light sensor indicates daytime conditions, the body control module (BCM) grounds the DRL relay control circuit energizing the DRL relay. With the DRL relay energized, the switch contacts close and voltage is applied to the DRL 1 and DRL 2 fuses to the left and right low beam headlamps. Any function or condition that turns on the headlamps will cancel DRL operation.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, with a scan tool command the Low Beams ON and OFF. The low beam headlamps should turn ON and OFF when changing between the commanded states. If the low beam headlamps do not turn ON and OFF when commanded, refer to «Headlamps Malfunction»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system) .
  2. Ignition ON, park brake released, verify with a scan tool the Park Brake Switch parameter displays Released. If not the specified value, refer to «Brake Warning Indicator Malfunction»(/chevrolet/impala/ix-2006-2016/remont/mechanical-hydraulic/#hydraulic-brake-system) .
  3. Ignition ON, with a scan tool command the DRL ON and OFF. The low beam headlamps should turn ON and OFF when changing between the commanded states. If the low beam headlamps turn ON and OFF when commanded, refer to Ambient Light Sensor Malfunction. If the low beam headlamps do not turn ON and OFF when commanded, refer to Daytime Running Lamps Malfunction.

Ambient Light Sensor Malfunction

  1. Ignition OFF, disconnect the harness connector at the ambient light sensor.
  2. Ignition 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. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V. If less than the specified range, test the signal circuit terminal A or a short to ground. If the circuit tests normal, replace the BCM
  4. Install a 3 A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool Ambient Light Sensor parameter is less than 1.96 V. 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 BCM.
  5. If all circuits test normal, test or replace the ambient light sensor.

Daytime Running Lamps Malfunction

  1. Ignition OFF, disconnect the X4 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal H2.
  3. Command the DRL 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 BCM. 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 BCM.
  4. Ignition OFF, connect the X4 harness connector at the underhood fuse block.
  5. Disconnect the X3 harness connector at the underhood fuse block.
  6. Connect a test lamp between the control circuit terminal B2 and ground.
  7. Command the DRL 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 underhood fuse block. 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 underhood fuse block.
  8. If all circuits test normal, replace the underhood fuse block.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Daytime Running Lamp (DRL) Ambient Light Sensor Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Fog Lamp Switch Signal222
Fog Lamp Relay Control11B2530 00
Fog Lamp Control111
Fog Lamp - LF Ground1
Fog Lamp - RF Ground1
Headlamp Switch Ground2
1. Front Fog Lamps Malfunction 2. Front Fog Lamp Switch Malfunction

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

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Front Fog Lamp Switch parameter while activating the fog lamp switch. The parameter should change between Active and Inactive. If the parameter does not change between the commanded states, refer to Fog Lamp Switch Malfunction.
  2. Turn the fog lamps ON and OFF with the fog lamps switch. The fog lamps should turn ON and OFF as selected. If the fog lamps do not change between the selected states, refer to Fog Lamp Malfunction.
  3. Command the Display Test ON and OFF with a scan tool. The fog lamps indicator should turn ON and OFF when changing between the commanded states. It the fog lamps indicator illuminates during the test, replace the BCM. If the fog lamps indicator odes not illuminate during the test or remains illuminated at all times, replace the instrument cluster.

Fog Lamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Front Fog Lamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 6 and the ground circuit terminal 8. Verify the scan tool Front Fog Lamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the headlamp switch.

Fog Lamps Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal H5.
  3. Command the Fog 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 BCM. 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 BCM.
  4. Ignition OFF, connect the X2 harness connector at the underhood fuse block.
  5. Disconnect the harness connector at the appropriate fog lamp.
  6. Ignition 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 a test lamp between the control circuit terminal A and ground.
  8. Command the Fog 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 underhood fuse block. 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 underhood fuse block.
  9. If all circuits test normal, test or replace the fog lamp.

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 BCM.
  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. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Front Fog Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  4. «Front Fog Lamp Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  5. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Hazard Switch Signal111
Hazard Switch Ground11
1. Hazard Lamps Malfunction

The hazard flashers may be activated in any power mode. The hazard switch is located on the turn signal/multifunction switch and is permanently grounded. When the hazard switch is placed in the ON position, ground is applied through the hazard switch signal circuit to the body control module (BCM). The BCM supplies battery voltage to all four turn signal lamps in an ON and OFF duty cycle. When the hazard switch is activated, the BCM sends a serial data message to the instrument panel cluster (IPC) requesting both turn signal indicators to be cycled ON and OFF.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  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 H. 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 C for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal C 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 and open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the turn signal/multifunction switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Turn Signal Multifunction Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/steering-column-switches/#steering-wheel-and-steering-column)
  2. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Flash to Pass Switch Signal444
High Beam Switch Signal441 4
Headlamp Switch Headlamps ON SignalB257A 001B257A 00
Headlamp Switch Headlamps OFF SignalB257A 001B257A 00
Park Lamp Switch Park Lamps ON SignalB257A 00B257A 00B257A 00
Headlamp High Beam Relay Control33B2580 00
Headlamp Low Beam Relay Control22B2575 00
LF High Beam Headlamp Control333
LF Low Beam Headlamp Control222
RF High Beam Headlamp Control333
RF Low Beam Headlamp Control222
LF Headlamp Ground2
RF Headlamp Ground2
Headlamp Switch Ground1
Turn Signal/Multifunction Switch Ground4
1. Headlamp Switch Malfunction 2. Headlamps Malfunction - Low Beam 3. Headlamps Malfunction - High Beam 4. Turn Signal/Multifunction Switch

The vehicle headlamps are controlled by the body control module (BCM) based on inputs from the headlamp switch and the turn signal/multifunction switch. The headlamp switch has four positions: Off, Auto, Park, and Headlamps. The default headlamp switch position is Auto, in which the BCM uses the ambient light sensor to determine when headlamps are needed. The Off portion of the headlamp switch is a momentary switch which overrides the automatic headlamps and will turn off the vehicle headlamps. When in the Off position, the headlamp switch grounds the headlamp switch headlamps off signal circuit, prompting the BCM to turn off the headlamps. The Park position of the headlamp switch will only illuminate the vehicle parking lamps. The Headlamp position of the headlamp switch will illuminate both the parking lamps, as well has the headlamps. With the headlamp switch in the Headlamp position, the headlamp switch headlamps on signal circuit is grounded, prompting the BCM to turn on the headlamps, regardless of other factors such as ambient light.

The headlamp high beams are controlled through the flash to pass switch and the headlamp dimmer switch, both located in the turn signal/multifunction switch. The flash to pass switch is a momentary type switch, designed to illuminate the high beams as long as the switch is held. With the switch closed, the flash to pass switch signal circuit is grounded, prompting the BCM to turn on the high beam lamps. The headlamp dimmer switch allows the operator to select between full time high or low beam operation. Unlike the flash to pass switch, it is not a momentary switch. When the headlamp dimmer switch is in the high beam position, the headlamp dimmer switch high beam signal circuit is grounded. This prompts the BCM to turn on the high beam lamps.

The BCM controls the headlamps based on the inputs explained above. When a low beam request is received, the BCM grounds the headlamp low beam relay control circuit. This energizes the coil in the LOW BEAM PCB relay, causing the relay switch to close. This then applies B+ to both low beam headlamps through the LT LO BEAM and RT LO BEAM fuses, illuminating the low beam headlamps. When a high beam request is received, the BCM grounds the headlamp high beam relay control circuit. This energizes the coil in the HIGH BEAM PCB relay, causing the relay switch to close. This then applies B+ to both high beam headlamps through the LT HI BEAM and RT HI BEAM fuses, illuminating the high beam headlamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__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 reading should change between Active and Inactive. If the reading does not change between the specified values, refer to Headlamp Switch Malfunction.
  2. Ignition ON, observe the scan tool Auto Hdlp. Disable Sw. parameter while turning the headlamp switch ON and OFF. The reading should change between Active and Inactive. If the reading does not change between the specified values, refer to Headlamp Switch Malfunction.
  3. Observe the scan tool Flash to Pass Switch parameter while applying and releasing the turn signal/multifunction switch. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction.
  4. Observe the scan tool High Beam Select Switch parameter while applying and releasing the high beam select switch. The reading should toggle between Active and Inactive. If the reading does not change between the specified values, refer to Turn Signal/Multifunction Switch Malfunction.
  5. Command the Low Beams ON and OFF with a scan tool. The low beam headlamps should turn ON and OFF when commanded. If the low beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - Low Beam.
  6. Command the High Beams ON and OFF with a scan tool. The high beam headlamps should turn ON and OFF when commanded. If the high beam headlamps do not turn ON and OFF when commanded, refer to Headlamps Malfunction - High Beam.
  7. Command the Display Test ON and OFF with a scan tool. The high beam indicator should turn ON and OFF when changing between the commanded states. If the high beam indicator illuminates during the test, replace the BCM. If the high beam indicator does not illuminate during the test or remain illuminated at all times, replace the instrument cluster.

Headlamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 8. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Headlamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 1 for short to ground. If the circuit tests normal, replace the BCM.
  4. Verify the scan tool Auto Hdlp. Disable Sw. parameter is Inactive.
  5. If not the specified value, test the signal circuit terminal 3 for short to ground. If the circuit tests normal, replace the BCM.
  6. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool Headlamp 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 BCM.
  7. Install a 3 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Auto Hdlp. Disable Sw. 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 BCM.
  8. If all circuits test normal, test or replace the headlamp switch.

Turn Signal/Multifunction Switch Malfunction

  1. Ignition OFF, disconnect the X2 harness connector at the turn signal/multifunction switch.
  2. 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.
  3. Ignition ON, 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 BCM.
  4. 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 BCM.
  5. Install a 3 A 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 and open/high resistance. If the circuit tests normal, replace the BCM.
  6. Install a 3 A 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 and open/high resistance. If the circuit tests normal, replace the BCM.
  7. If all circuits test normal, test or replace the turn signal/multifunction switch.

Headlamps Malfunction - Low Beam

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal A5.
  3. Command the Low Beams 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 BCM. 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 BCM.
  4. Ignition OFF, disconnect the harness connector at the appropriate low beam headlamp.
  5. 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.
  6. Connect a test lamp between the control circuit terminal A and ground.
  7. Command the Low Beams 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 underhood fuse block. 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 underhood fuse block.
  8. If all circuits test normal, test or replace the low beam headlamp.

Headlamps Malfunction - High Beam

  1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
  2. Connect a test lamp between B+ and the control circuit terminal C6.
  3. Command the High Beams 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 BCM. 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 BCM.
  4. Ignition OFF, disconnect the harness connector at the appropriate high beam headlamp.
  5. 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.
  6. Connect a test lamp between the control circuit terminal A and ground.
  7. Command the High Beams 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 underhood fuse block. 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 underhood fuse block.
  8. If all circuits test normal, test or replace the high beam headlamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  2. «Headlamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  4. «Turn Signal Multifunction Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/steering-column-switches/#steering-wheel-and-steering-column)
  5. «Headlamp Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  6. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM or IPC replacement, setup and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
I/P Dimming Voltage ReferenceB1395 03, B3600 03B1395 031, 2
Instrument Panel Lamps Dimmer Switch SignalB3600 03B3600 031, 2
Instrument Panel Lamp ControlB2652 0011
LED Dimming ControlB2610 0022
Headlamp Switch Ground3
1. Instrument Panel Lamps Malfunction 2. LED Malfunction 3. Headlamps and Dimmer Switch Malfunction

The body control module (BCM) supplies a voltage reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage from the CHMSL/BCK-UP fuse through the instrument panel lamp supply voltage circuit, the backlight lamp control circuit, and the LED dimming supply circuit illuminating the LED and I/P panel lamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Dimming Control Signal parameter while operating the dimmer switch from high to low. The parameter should change from a high percent to a low percent as the switch is rotated. If the parameter does not change, refer to Dimmer Switch Circuit Test.
  2. If the scan tool dimmer control operates normal, refer to Interior Backlighting Circuit Test.

Dimmer Switch Circuit Test

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Dimming Control Signal parameter is less than 0.2 volts. If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Ignition ON, test for B+ between the voltage reference circuit terminal 15 and ground. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3A fused jumper wire between the signal circuit terminal 13 and the voltage reference circuit terminal 15. Verify the scan tool Dimming Control Signal parameter is greater than 2.6 volts. If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  6. If all circuits test normal, test or replace the headlamp switch.

Interior Backlighting Circuit Test

  1. Ignition OFF, disconnect the X3 harness connector at the BCM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the BCM and disconnect the harness connector at the component with the inoperative backlighting.
  4. Verify that a test lamp illuminates between the appropriate ground circuit terminal listed below and B+. Headlamp Switch terminal 8 Instrument Panel Cluster (IPC) terminal 6 Driver Window Switch terminal B X1 Driver Door Lock Switch terminal B Outside Rearview Mirror Switch terminal B Passenger Window Switch terminal C Passenger Door Lock Switch terminal B Radio terminal 8 X1 HVAC Control Module terminal 10 X1 Driver Information Display Switch terminal 5 Left Steering Wheel Controls terminal 8 Right Steering Wheel Controls terminal 1 If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  5. Connect a test lamp between the appropriate control circuit terminal listed below and ground. Incandescent Dimming Headlamp Switch terminal 7 Instrument Panel Cluster (IPC) terminal 8 Driver Window Switch terminal F X2 Driver Door Lock Switch terminal A Outside Rearview Mirror Switch terminal E Passenger Window Switch terminal B Passenger Door Lock Switch terminal A LED Dimming Radio terminal 7 X1 HVAC Control Module terminal 1 X1 Driver Information Display Switch terminal 4 Left Steering Wheel Controls terminal 6 Right Steering Wheel Controls terminal 2
  6. Ignition ON, command the appropriate Incandescent Dimming or LED Dimming 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 BCM If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  7. 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. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Front Side Door Window Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/heated-glassdefoggers/#fixed-and-moveable-windows)
  3. «Door Lock Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/door-locks-anti-theft-systems/#power-door-lock-system-and-release-systems)
  4. «Power Mirror Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/mirrors/#mirror-system)
  5. «Steering Wheel Control Switch Assembly Replacement»(/chevrolet/impala/ix-2006-2016/remont/memory-modules/#secondary-and-configurable-customer-control-system)
  6. «Driver Information Display Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/gauges-instrument-panels/#instrument-panel-system-displays-and-gauges)
  7. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM, HVAC, IPC, or Radio replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Park Lamp Switch On SignalB257A 00, 2B257A 00B257A 00*, 1
Park Lamp Relay Control21B2585 00
Left Park Lamp Control333
Right Park Lamp Control444
Ground - Left Park Lamp33
Ground - Right Park Lamp44
Ground - Headlamp Switch1
* Internal damage to the headlamp switch may occur if shorted to B+ 1. All park lamps inoperative 2. All park lamps always on 3. Left park lamps malfunction 4. Right park lamps malfunction

The vehicle park, license, and tail lamps are controlled by the body control module (BCM) based on an input from the headlamp switch. The headlamp switch has four positions: Off, Auto, Park, and Headlamps. The default headlamp switch position is Auto, in which the BCM uses the ambient light sensor to determine when exterior lamps are needed. The Off portion of the headlamp switch is a momentary switch which overrides the automatic lamps and will turn off the vehicle lamps. The Park position of the headlamp switch will only illuminate the vehicle parking lamps. The Headlamp position of the headlamp switch will illuminate both the parking lamps, as well as the headlamps. With the headlamp switch in the Park position, the park lamp switch on signal circuit is grounded prompting the BCM to turn ON the exterior lamps, regardless of other factors such as ambient light.

When a park lamp request is received, the BCM grounds the park lamp relay control circuit. This energizes the PARK LP PCB relay. Battery voltage is then applied through the switch side of the relay, the LT PARK and RT PARK fuses illuminating the front park, license, tail, and marker lamps.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool BCM Parklamp Switch parameter while cycling the headlamp switch between the Park and Auto positions. The parameter should change between Active and Inactive. If the parameter does not change between the specified values, refer to Headlamp Switch Malfunction.
  2. Command the Parking Lamps ON and OFF with a scan tool. The front park, license, and tail lamps should turn ON and OFF when changing between the commanded states. If all of the lamps are always OFF or remain ON, refer to the Park Lamp Relay Malfunction. If one or more of the lamps is always OFF, refer to Park Lamps Malfunction.

Headlamp Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Ignition OFF, verify that a test lamp illuminates between the ground circuit terminal 8 and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Parklamp Switch parameter is Inactive. If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Parklamp Switch parameter is Active. If not the specified value, test the signal circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the BCM.
  5. If all circuits test normal, test or replace the headlamp switch.

Park Lamp Relay Malfunction

  1. Ignition OFF, disconnect the harness connector X2 at the underhood fuse block.
  2. Connect a test lamp between the control circuit terminal K2 and B+.
  3. Ignition ON, 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 BCM. 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 BCM.
  4. If the circuit tests normal, replace the underhood fuse block.

Park Lamps Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate exterior lamp.
  2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal listed below and ground. Marker Lamps terminal B Tail Lamps terminal B License Lamp terminal B Tail/Stop/Turn Signal Lamps terminal G Front Park/Turn Signal Lamps terminal G 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 listed below and ground. Marker Lamps terminal A Tail Lamps terminal A License Lamp terminal A Tail/Stop/Turn Signal Lamps terminal B Front Park/Turn Signal Lamps terminal B
  4. Ignition ON, 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 voltage. If the circuit tests normal, replace the underhood fuse block. 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 underhood fuse block.
  5. If all circuits test normal, test or replace the park lamp.

Component Testing

Headlamp Switch

  1. Ignition OFF, disconnect the harness connector at the headlamp switch.
  2. Test for infinite resistance between the signal terminal 1 and the ground terminal 8 with the switch in the Auto position. If not the specified value, replace the headlamp switch.
  3. Test for less than 2.0 ohms between the signal terminal 1 and the ground terminal 8 with the switch in the Headlamp ON position. If greater than the specified value, replace the headlamp switch.
  4. Test for infinite resistance between the signal terminal 2 and the ground terminal 8 with the switch in the Auto position. If not the specified value, replace the headlamp switch.
  5. Test for less than 2.0 ohms between the signal terminal 2 and the ground terminal 8 with the switch in the Park position. If greater than the specified value, replace the headlamp switch.
  6. Test for infinite resistance between the signal terminal 3 and the ground terminal 8 with the switch in the Auto position. If not the specified value, replace the headlamp switch.
  7. Test for less than 2.0 ohms between the signal terminal 3 and the ground terminal 8 with the switch in the Off position. If greater than the specified value, replace the headlamp switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Switch Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Headlamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Tail Lamp Bulb Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  4. «Rear Turn Signal Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  5. «Rear License Plate Lamp Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  6. «Accessory Wiring Junction Block Replacement»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-repair-instructions)
  7. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Body Control Module (BCM) B+ Terminal 1 X411
Body Control Module (BCM) B+ Terminal 3 X422
Brake Pedal Position Sensor 5-Volt ReferenceC0277 06, C0890 03C0277 06C0277 06
Brake Applied SignalC0297 0044
Brake Pedal Position Sensor SignalC0277 06C0277 06C0277 07C0277 09, C0277 4B
Center High Mounted Stop Lamp (CHMSL) ControlB3445 00, B3884 0033
Left Rear Stop/Turn Lamp Control111
Right Rear Stop/Turn Lamp Control222
Brake Pedal Position Sensor Low ReferenceC0277 061
Center High Mounted Stop Lamp (CHMSL) Ground3
Left Rear Stop/Turn Lamp Ground1
Right Rear Stop/Turn Lamp Ground2
1. Stop Lamps Malfunction - Left 2. Stop Lamps Malfunction - Right 3. Center High Mounted Stop Lamp (CHMSL) Malfunction 4. Cruise Control Malfunction

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The brake pedal position sensor provides an analog voltage signal that will increase as the brake pedal is applied. The body control module (BCM) provides a low reference signal and a 5 V If the left and right turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the instrument cluster. reference voltage to the brake pedal position sensor. When the variable signal reaches a voltage threshold indicating the brakes have been applied, the BCM will apply battery voltage to the stop lamps, center high mounted stop lamp (CHMSL), transmission control module (TCM), and engine control module (ECM).

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Brake Applied Output Signal parameter as you apply and unapply the brake pedal. The reading should cycle between OFF and ON as the brake pedal is applied and released. If the reading does not change as the brake pedal is applied and released, refer to Brake Pedal Position Sensor Malfunction.
  2. With a scan tool, command the LR Turn Signal ON and OFF. The LR turn signal should turn ON and OFF when changing between the commanded states. If the LR turn signal does not illuminate when commanded, refer to Stop Lamps Malfunction.
  3. With a scan tool, command the RR Turn Signal ON and OFF. The RR turn signal should turn ON and OFF when changing between the commanded states. If the RR turn signal does not illuminate when commanded, refer to Stop Lamps Malfunction.

Brake Pedal Position Sensor Malfunction

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

Stop Lamps Malfunction

  1. Ignition OFF, disconnect the X4 harness connector at the BCM.
  2. Verify that a test lamp illuminates between the B+ circuit terminal 1 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 3 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, connect the X4 harness connector at the BCM.
  5. Disconnect the harness connector at the appropriate stop lamp.
  6. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal G and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Connect a test lamp between the control circuit terminal A and ground.
  8. Ignition ON, command the stop lamp ON and OFF by commanding the appropriate Rear Turn Signal parameter 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 BCM. 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 BCM.
  9. If all circuits test normal, replace the stop lamp.

Center High Mounted Stop Lamp Malfunction

  1. Ignition OFF, disconnect the harness connector at the center high mount stop lamp.
  2. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal A 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 B and the ground circuit terminal A.
  4. Ignition ON, command the stop lamps ON and OFF by applying and releasing the brake pedal. 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 BCM. 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 BCM.
  5. If all circuits test normal, test or replace the center high mount stop lamp.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Brake Pedal Position Sensor Calibration»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-calibration)
  2. «Brake Pedal Position Sensor Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system__brake-pedal-position-sensor-replacement)
  3. «High Mount Stop Lamp Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  4. «Rear Turn Signal Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  5. «Tail Lamp Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  6. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach
  3. «Diagnostic Procedure Instructions»(/chevrolet/impala/ix-2006-2016/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+, BCM X4 terminal 122
B+, BCM X4 terminal 2B2615 00, 5B2615 00, 5
B+, BCM X4 terminal 377
Left Turn Signal Switch Signal222
Right Turn Signal Switch Signal333
Left Front Turn Signal Lamp Control444
Right Front Turn Signal Lamp Control555
Left Rear Stop/Turn Lamp Control666
Right Rear Stop/Turn Lamp Control777
Ground - Turn Signal/Multifunction Switch1
Ground - LF Park/Turn Signal Lamp4
Ground - RF Park/Turn Signal Lamp5
Ground - Left Tail/Stop and Turn Signal Lamp6
Ground - Right Tail/Stop and Turn Signal Lamp7
1. All turn signals inoperative 2. Left turn signals malfunction 3. Right turn signals malfunction 4. Left front turn signal malfunction 5. Right front turn signal malfunction 6. Left rear stop/turn signal malfunction 7. Right rear stop/turn signal malfunction

The body control module (BCM) controls the vehicle turn signals based on inputs from the turn signal/multifunction switch. With the turn signal/multifunction switch in the left turn position, a ground path is provided on the left turn signal switch signal circuit, indicating a left turn signal request. With the turn signal/multifunction switch in the right turn position, a ground path is provided on the right turn signal switch signal circuit, indicating a right turn signal request. When the specific request is seen, the BCM will pulse the respective turn signal lamp supply voltage circuits, illuminating the turn signal lamps.

When a turn signal request is seen by the BCM, a serial data message is sent to the instrument panel cluster (IPC) requesting the respective turn signal indicator be pulsed.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures)
  4. «Wiring Repairs»(/chevrolet/impala/ix-2006-2016/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition ON, observe the scan tool Right Turn Signal Switch and Left Turn Signal Switch parameters while cycling the turn signal switch between the right and left positions. The readings should change between Active and Inactive. If the parameters do not change between the selected states, refer to Turn Signal Switch Malfunction.
  2. Ignition ON, observe the right and left turn signal lamps while cycling the turn signal switch between the right and left positions. Verify the turn signal lamps turn ON and OFF. If the turn signal lamps do not cycle between the selected states, refer to Turn Signal Lamp Malfunction.
  3. Command the Display Test ON and OFF with a scan tool. The left and right turn signal indicators should turn ON and OFF when changing between the commanded states. If the left and right turn signal indicators illuminate during the test, replace the BCM. If the left and right turn signal indicators do not illuminate during the test or remain illuminated at all times, replace the instrument cluster.

Turn Signal Switch Malfunction

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

Turn Signal Lamp Malfunction

  1. Ignition OFF, disconnect the harness connect X4 at the BCM.
  2. Ignition ON, verify a test lamp illuminates between the B+ circuits listed below and ground. B+ terminal 1 B+ terminal 2 B+ terminal 3 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 fuse is open, test the appropriate control circuit(s) listed below for a short to ground. LT T/SIG Fuse - terminal 1 X5 and terminal 4 X5 RT T/SIG Fuse - terminal 2 X5 INT LIGHTS Fuse - terminal 5 X4
  3. Ignition OFF, disconnect the harness connector at the appropriate turn signal lamp.
  4. Verify that a test lamp illuminates between the ground circuit terminal G and B+. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  5. Connect a test lamp between the control circuit terminal A and the ground circuit terminal G.
  6. Ignition ON, command the appropriate turn signal 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 BCM. 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 BCM.
  7. If all circuits test normal, test or replace the turn signal lamp.

Turn Signal/Multifunction Switch

  1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Test for infinite resistance between the signal terminals listed below and the ground circuit terminal E with the switch in the neutral position. Signal terminal D Signal terminal F If not the specified value, replace the turn signal/multifunction switch.
  3. Test for less than 2.0 ohms between the signal terminal D and the ground terminal E with the switch in the left turn position. If greater than the specified range, replace the turn signal/multifunction switch.
  4. Test for less than 2.0 ohms between the signal terminal F and the ground terminal E with the switch in the left turn position. If greater than the specified range, replace the turn signal/multifunction switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Headlamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  2. «Rear Turn Signal Lamp Bulb Replacement»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system)
  3. «Turn Signal Multifunction Switch Replacement»(/chevrolet/impala/ix-2006-2016/remont/steering-column-switches/#steering-wheel-and-steering-column)
  4. «Control Module References»(/chevrolet/impala/ix-2006-2016/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for BCM and IPC 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

The brake pedal position sensor (BPPS) receives a low reference signal and a 10-volt reference signal from the body control module (BCM). Whenever the brake pedal is applied, the brake pedal position sensor applies a variable voltage signal to the BCM through the stop lamp switch signal circuit. Brake pedal position sensor calibration must be performed after the brake pedal position sensor or BCM have been serviced. The calibration procedure will set brake pedal position sensor home value. This value is used by the BCM to determine the action of the driver applying the brake system and to provide this information to the vehicle subsystems via the class 2 communication bus.

Calibration Procedure

IMPORTANTIf the master brake cylinder has been replaced, verify that the correct pushrod is installed before attempting to calibrate the brake pedal position sensor.
  1. Turn ON the ignition, with the engine OFF.
  2. Install a scan tool, select the proper vehicle and options.
  3. Navigate to the BCM menu.
  4. Select Module Setup menu item.
  5. Select the BPPS sensor calibration procedure and follow the directions displayed on the screen.

Brake Pedal Position Sensor Replacement

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.

Scheme 16

Scheme 16: Brake Pedal Position Sensor Replacement
Scheme 16: Brake Pedal Position Sensor Replacement
CalloutComponent Name
1Brake Pedal Position Sensor Assembly Tip: Disconnect the electrical connector.
2Brake Pedal Position Sensor Bolt CAUTION: Refer to Fastener Caution . Tip: Calibrate the position sensor. Refer to Brake Pedal Position Sensor Calibration . Do not reuse the position sensor or bolt. Always use a new sensor and bolt. Tighten: 2 N.m (18 lb in)
CAUTION
Refer to Fastener Caution .

Scheme 17

Scheme 17: Headlamp Switch Replacement (Impala)
Scheme 17: Headlamp Switch Replacement (Impala)
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Switch Assembly, Head lamp Instrument Panel Dimmer Tip: Disconnect the electrical connector.

Scheme 18

Scheme 18: Daytime Running Lamp (DRL) Ambient Light Sensor Replacement
Scheme 18: Daytime Running Lamp (DRL) Ambient Light Sensor Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Instrument Panel Upper Trim Panel Refer to Instrument Panel Upper Trim Panel Replacement .
2Ambient Light Sensor Assembly

Removal Procedure

  1. Remove the upper radiator baffle. Refer to «Radiator Air Upper Baffle and Deflector Replacement»(/chevrolet/impala/ix-2006-2016/remont/cooling-system-mechanical/#engine-cooling-system) .
  2. Disconnect the electrical connectors.
  3. Remove the headlamp flasher bolts at the front radiator support (2).
  4. Remove the headlamp flasher.

Installation Procedure

  1. Position the headlamp flasher (1) to the front radiator support (2).
  2. Install the headlamp flasher bolts. Tighten: Tighten the bolts to 10 N.m (89 lb in).
  3. Connect the electrical connectors.
  4. Install the upper radiator baffle. Refer to «Radiator Air Upper Baffle and Deflector Replacement»(/chevrolet/impala/ix-2006-2016/remont/cooling-system-mechanical/#engine-cooling-system) .

Scheme 19

Scheme 19: Reading Lamp Bulb Replacement
Scheme 19: Reading Lamp Bulb Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Reading Lamp Lens (Qty: 2)
2Reading Lamp Bulb (Qty: 2)

Scheme 20

Scheme 20: Instrument Panel Courtesy Lamp Bulb Replacement
Scheme 20: Instrument Panel Courtesy Lamp Bulb Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications . Preliminary Procedure: Remove the instrument panel (I/P) insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Right Side or Instrument Panel Insulator Panel Replacement - Left Side .
1Courtesy Lamp, Instrument Panel Tip: Disconnect the electrical connector.
  1. Lower the sunshade and open the illuminated mirror door.
  2. Insert a small flat-bladed tool at the outer edge of the lamp lens in the slot. Carefully press down to remove the lens.
  3. Remove the bulb.
  1. Install the bulb.
  2. Align the upper lens tab to the opening. Insert the upper edge of the lens.
  3. Insert a small flat-bladed tool at the outer edge of the lamp lens. Carefully press up to install the lens.
  4. Close the illuminated mirror door and raise the sunshade.

Scheme 21

Scheme 21: Dome Lamp Replacement (Impala)
Scheme 21: Dome Lamp Replacement (Impala)
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Lamp Assembly, Dome Reading Tip: Pry open the driver side. Disconnect the electrical connectors.

Scheme 22

Scheme 22: Dome Lamp Bulb Replacement (Impala)
Scheme 22: Dome Lamp Bulb Replacement (Impala)
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
1Lens, Dome Lamp Tip: Pry open the driver side.
2Bulb, Dome lamp

Scheme 23

Scheme 23: Headlamp Replacement
Scheme 23: Headlamp Replacement
CalloutComponent Name
Preliminary Procedures Open the hood. Release the inner headlamp retainer by pulling the retainer upward in order to release the headlamp.
1Headlamp Assembly Bolt CAUTION: Refer to Fastener Caution . Tighten: 6 N.m (53 lb in)
2Headlamp Lock Pin Tip: Pull headlamp from the outboard edge in order to release the lock pin from the fender flange retainer.
3Forward Lamp Harness Connector Tip: Disconnect the electrical connector before removing the headlamp from the vehicle.
4Headlamp Assembly WARNING: Refer to Halogen Bulb Warning .
CAUTION
Refer to Fastener Caution .
WARNING
Refer to Halogen Bulb Warning .

Scheme 24

Scheme 24: Headlamp Bulb Replacement
Scheme 24: Headlamp Bulb Replacement
CalloutComponent Name
Preliminary Procedures Open the hood. Remove either the LH of RH headlamp assembly. Refer to Headlamp Replacement .
1Daytime Running and Front Park and Turn Signal Lamp Assembly WARNING: Refer to Halogen Bulb Warning .
2Park Lamp Assembly Tip: Pull outward on the housing in order to access the electrical connector.
3Headlamp Bulb Accessory Cover Tip: Turn the cover counterclockwise in order to remove.
4Headlamp Bulb (LO Beam) WARNING: Refer to Halogen Bulb Warning . Tip: Disconnect the electrical connector from the headlamp bulb socket and turn bulb socket a quarter turn counterclockwise in order to remove.
5Headlamp Bulb Accessory Cover Tip: Turn the cover counterclockwise in order to remove.
6Headlamp Bulb (HI Beam) WARNING: Refer to Halogen Bulb Warning . Tip: Disconnect the electrical connector from the headlamp bulb socket and turn bulb socket a quarter turn counterclockwise in order to remove.
7Front Park and Turn Signal Socket Tip: Turn lamp socket counterclockwise in order to remove from the headlamp assembly.
8Front Park and Turn Signal Bulb Tip: Pull the park and turn signal lamp bulb straight from the bulb socket.
9Forward Lamp Harness Connector
WARNING
Refer to Halogen Bulb Warning .
WARNING
Refer to Halogen Bulb Warning .
WARNING
Refer to Halogen Bulb Warning .

Headlamp Aiming

The vehicle has a visual optical headlamp aiming system. The aim has been preset at the factory and should need no further adjustment

However, If the vehicle is damaged in an accident, the headlamp aim may be affected and adjustment may be necessary.

The vehicle should be properly prepared as follows

  1. The vehicle should be placed so the headlamps are 7.6 m (25 ft) from a light colored wall or other flat surface.
  2. The vehicle must have all four tires on a perfectly level surface which is level all the way to the wall or other flat surface.
  3. The vehicle should be placed so it is perpendicular to the wall or other flat surface.
  4. The vehicle should not have any snow, ice or mud on it.
  5. The vehicle should be fully assembled and all other work stopped while headlamp aiming is being done.
  6. The vehicle should be normally loaded with a full tank of fuel and one person or 75 kg(160 lbs) on the driver seat.
  7. Tires should be properly inflated.

Headlamp aiming is done with the vehicle's low-beam headlamps. The high-beam headlamps will be correctly aimed if the low-beam headlamps are aimed properly.

The vertical headlamp aiming screws are located under the hood near the headlamps.

The adjustment screw can be turned with a 6 mm male hex.

To adjust the vertical aim on the headlamps, do the following

  1. Find the aim dot on the lens of the low-beam lamp.
  2. Measure the distance from the ground to the aim dot on the lamp. Record the distance.
  3. At the wall or other flat surface, measure from the ground upward the recorded distance from Step 2 and draw or tape a horizontal line the width of the vehicle.
  4. Turn on the low-beam headlamps and place a piece of cardboard or equivalent in front of the headlamp not being aimed. This should allow only the beam of light from the headlamp being aimed to be seen on the flat surface.
  5. Turn the vertical aiming screw until the headlamp beam is aimed to the horizontal tape line. The top edge of the cut-off should be positioned at the bottom edge of the horizontal tape line.
  6. Repeat Steps 4 and 5 for the opposite headlamp.

Scheme 25

Scheme 25: Front Fog Lamp Replacement
Scheme 25: Front Fog Lamp Replacement
CalloutComponent Name
Preliminary Procedures Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle . Remove either the LF or RF front fender liner. Refer to Front Fender Liner Replacement . Disconnect fog lamp bulb socket electrical connector.
1Front Fog Lamp Adjuster Screw Procedure Remove the adjuster screw from the fog lamp bracket and lamp assembly. Count the number of turns when removing the adjuster screw for a reference upon installation. Aim the fog lamp after installation. Refer to Fog Lamp Aiming .
2Front Fog Lamp Screws (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
3Front Fog Lamp Assembly Tip: Remove the lamp assembly from the fog lamp bracket.
4Front Fog Lamp Bulb WARNING: Refer to Halogen Bulb Warning . Tip: Turn the bulb socket counterclockwise and remove from lamp assembly.
CAUTION
Refer to Fastener Caution .
WARNING
Refer to Halogen Bulb Warning .

Scheme 26

Scheme 26: Front Fog Lamp Bulb Replacement
Scheme 26: Front Fog Lamp Bulb Replacement
CalloutComponent Name
Preliminary Procedures Remove either the LF or RF headlamp assembly. Refer to Headlamp Replacement . Disconnect the fog lamp electrical connector.
1Front Fog Lamp Projector Bulb WARNING: Refer to Halogen Bulb Warning . Tip: Twist the bulb socket counterclockwise to remove from the lamp housing.
2Front Fog Lamp Projector Housing
WARNING
Refer to Halogen Bulb Warning .

Fog Lamp Aiming

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

There is no horizontal adjustment for aiming the front fog lamp assemblies on this vehicle.

  1. 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, if other service has been performed on the vehicle. Ensure the fuel level is full. Place the vehicle on a level surface 1.52 m (5 ft) away from a target screen. Stop all other operations of work on the vehicle. Jounce the vehicle to settle the suspension. Cover the headlamps while aiming the fog lamps.
  2. Turn the front fog lamps ON.
  3. Adjust the fog lamp up or down until the top edge of the high intensity zone on the screen is 102 mm (4 in) below the horizontal centerline (2), within the range of 0 mm (0 in) (3) to 203 mm (8 in) (5), below the horizontal centerline, on the target screen.
  4. Turn OFF the front fog lamps.

Scheme 27

Scheme 27: High Mount Stop Lamp Replacement (Impala)
Scheme 27: High Mount Stop Lamp Replacement (Impala)
CalloutComponent Name
Preliminary Procedure: Remove the rear interior compartment lid trim. Refer to Rear Compartment Lid Inner Panel Trim Replacement .
1High Mounted Stop Lamp Assembly Nuts (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 4 N.m (35 lb in)
2High Mounted Stop Lamp Assembly Tip: Remove the high mounted stop lamp from the inside of the rear compartment lid mounting studs. Disconnect the electrical connector to the high mounted stop lamp.
3Rear Compartment Inner Panel Studs Tip: Ensure the studs are secure to the inner compartment panel upon reassemble.
CAUTION
Refer to Fastener Caution .

Scheme 28

Scheme 28: Backup Lamp Bulb Replacement
Scheme 28: Backup Lamp Bulb Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications . Preliminary Procedure: Remove either the LR or RR tail lamp assembly. Refer to Tail Lamp Replacement (Impala) .
1Socket, Reverse Lamp Bulb Tip: Twist the socket counterclockwise a quarter turn to remove.
2Bulb, Reverse Lamp Tip: Pull outward on the bulb in order to replace.

Scheme 29

Scheme 29: Rear License Plate Lamp Replacement (Impala)
Scheme 29: Rear License Plate Lamp Replacement (Impala)
CalloutComponent Name
1Rear License Plate Lamp Screws (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Rear License Lamp Procedure Pull downward on the lamp in order to access the lamp electrical connector on the inside of the rear bumper fascia. Twist the connector socket counterclockwise in order to remove from the lamp housing. Pull the bulb outward to remove from the socket.
3Rear License Plate Lens Tip: Snap lens into outer rear compartment lid upon installation.
CAUTION
Refer to Fastener Caution .

Scheme 30

Scheme 30: Tail Lamp Replacement (Impala)
Scheme 30: Tail Lamp Replacement (Impala)
CalloutComponent Name
Preliminary Procedures Open the rear compartment lid. Remove the nut securing the rear compartment trim the backside of the tail lamp assembly. Pull down the rear compartment trim liner.
1Tail Lamp Assembly Nuts (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 2 N.m (18 lb in)
2Trunk Trim Line Nut Tip: Ensure the trim liner nut is installed after the liner is repositioned in the rear compartment.
3Tail Lamp Assembly Tip: Pull rearward to remove and connect the electrical connector and push lamp inward in order to position the lamp to the body panel.
4Rear Lamp Harness Connector Ensure to connect the lamp harness connector before securing the lamp to the rear body panel.
CAUTION
Refer to Fastener Caution .

Scheme 31

Scheme 31: Tail Lamp Bulb Replacement (Impala)
Scheme 31: Tail Lamp Bulb Replacement (Impala)
CalloutComponent Name
Preliminary Procedure Remove either the LR or RR tail lamp assembly. Refer to Tail Lamp Replacement (Impala) .
1Rear Park Lamp Bulb Tip: Turn the lamp socket counterclockwise in order to remove.
2Park and Turn Signal Assembly Bulb Tip: Pull the bulb straight out of the lamp socket.
3Rear Back Up Assembly Bulb WARNING: Refer to Halogen Bulb Warning . Tip: Remove the bulb from the lamp socket by pulling the bulb straight outward from the socket.
WARNING
Refer to Halogen Bulb Warning .

Scheme 32

Scheme 32: Rear Turn Signal Lamp Bulb Replacement
Scheme 32: Rear Turn Signal Lamp Bulb Replacement
CalloutComponent Name
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications . Preliminary Procedure: Remove either the LR or RR tail lamp assembly. Refer to Tail Lamp Replacement (Impala) .
1Socket, Stop and Tail Lamp Tip: Twist the socket counterclockwise a quarter turn to remove.
2Bulb, Stop and Tail Lamp Tip: Pull outward on the bulb in order to replace.
  1. Open the rear compartment.
  2. Disconnect the electrical connectors from the rear compartment lid lamp(s).
  3. Disconnect the electrical connector from the flasher fuse (1).
  4. Remove the flasher fuse (1) if required.
  5. Remove the rear compartment lid lamp(s) from the rear compartment lid.
  1. Position the rear compartment lid lamp(s) from the rear compartment lid.
  2. Install the flasher fuse (1) if required.
  3. Connect the electrical connector to the flasher fuse (1).
  4. Connect the electrical connectors to the rear compartment lid lamp(s).
  5. Close the rear compartment.
  1. Open the rear compartment.
  2. Remove the lens from the rear compartment lid lamp. Inserted a small coin under the rear compartment lid lamp lens and then twist the coin.
  3. Remove the bulb from the rear compartment lid lamp socket.
  1. Install the bulb to the rear compartment lid lamp socket.
  2. Install the lens to the rear compartment lid lamp, pressing into place until fully seated.
  3. Close the rear compartment.
  1. Remove the rear seat back. Refer to «Rear Seat Back Cushion Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/seats/#seat-hardware-seat-trim-and-upholstery) .
  2. Remove the bolts from the rear window panel lamp bracket(s).
  3. Disconnect the electrical connector(s).
  4. Remove the rear window panel lamp(s) from the rear window panel.
  1. Connect the electrical connector.
  2. Position the rear window panel lamp bracket(s) to the rear window panel.
  3. Install the bolts to the rear window panel bracket(s). Tighten: Tighten the window panel bolts to 3 N.m (27 lb in).
  4. Install the rear seat back. Refer to «Rear Seat Back Cushion Replacement (Impala)»(/chevrolet/impala/ix-2006-2016/remont/seats/#seat-hardware-seat-trim-and-upholstery) .
  1. Remove the lens from the rear window panel lamp. Inserted a small coin under the rear window panel lamp lens and then twist the coin.
  2. Remove the bulb from the rear window panel lamp socket.
  1. Install the bulb to the rear window panel lamp socket.
  2. Install the lens to the rear window panel lamp, pressing into place until fully seated.
  1. Remove the spot lamp wiring harness push-in retainer from the windshield garnish molding, using a small flat bladed tool.
  2. Disconnect the electrical connector.
  3. Remove the spot lamp handle wedge key screw from the spot lamp handle. Loosen the wedge key screw a few turns then with a light tap with a suitable hammer to the wedge key screw will loosen it from the spot lamp outer tube shaft.
  4. Remove the spot lamp handle from the outer tube shaft.
  5. Remove the rubber grommet from the outer tube shaft.
  6. Loosen the spot lamp bracket set screw.
  7. Pull the spot lamp with the outer tube shaft out of the spot lamp mounting bracket and set aside.
  8. Remove the spot lamp mounting bracket screws.
  9. Remove the mounting bracket and the gasket from the windshield pillar.
  10. Clean the mounting surface of the windshield pillar.
  1. Install the mounting bracket and the gasket on to the spot lamp outer tube shaft.
  2. Apply a small amount of RTV sealer GM P/N 12345336 or Canadian P/N 12346286 or equivalent to the screw holes on the windshield pillar.
  3. Install the mounting bracket, the gasket and the spot lamp outer tube shaft through the windshield pillar.
  4. Install the spot lamp mounting bracket screws. Tighten: Tighten the spot lamp mounting bracket screws to 3.5 N.m (31 lb in).
  5. Rotate the spot lamp to the upright position. Point the spot lamp forward.
  6. Tighten the spot lamp mounting bracket set screw just enough in order to firmly hold the spot lamp in the upright position.
  7. Install the rubber grommet to the outer tube shaft.
  8. Install the spot lamp handle onto the outer tube shaft in the vertical down position until the handle bottoms out, and the flat detent on the outer tube shaft is exposed through the wedge key screw hole.
  9. Install the spot lamp wedge key screw. Tighten: Tighten the spot lamp wedge key screw to 7.5 N.m (66 lb in).
  10. Connect the electrical connector.
  11. Install the spot lamp wiring harness push-in retainer to the windshield garnish molding, pressing in until fully seated.
  12. Inspect the spot lamp for proper operation. The handle must rotate the spotlamp approximately 90 degrees about the spot lamp shaft axis from the parked position to the vertical position. The spot lamp head must rotate 360 degrees about its axis. The spot lamp must able to be turned ON/OFF independent of the ignition switch.
  13. If spot lamp adjustment and/or electrical diagnosis are required, refer to the following procedures. For spot lamp travel adjustment, refer to «Spot Lamp Travel Adjustment (Impala RPO 7X6, 7X7)»(/chevrolet/impala/ix-2006-2016/remont/exterior-lights/#lighting-system__spot-lamp-travel-adjustment-impala-rpo) . For electrical diagnosis, refer to «Power Distribution Schematics»(/chevrolet/impala/ix-2006-2016/remont/body-electrical/#wiring-systems-and-power-management-wiring-schematics-and-wiring-harness-routing-diagrams) .
  1. Remove the spot lamp wiring harness push-in retainer from the windshield garnish molding, using a small flat bladed tool.
  2. Disconnect the electrical connector.
  3. Remove the screw from the spot lamp bezel.
  4. Remove the spot lamp bezel from the spot lamp.
  5. Remove the lamp from the spot lamp.
  6. Remove spot lamp bulb retaining clip.
  7. Remove the spot lamp bulb from the spot lamp.
  8. Disconnect the spot lamp bulb electrical connector.
  1. Connect the spot lamp bulb electrical connector.
  2. Install the spot lamp bulb to the spot lamp.
  3. Install the spot lamp bulb retaining clip.
  4. Holding the spot lamp in position, install the spot lamp bezel to the spot lamp.
  5. Install the spot lamp bezel screws. Tighten: Tighten the spot lamp bezel screws to 2 N.m (18 lb in).
  6. Using a small flat-bladed tool, install the spot lamp wiring harness push-in retainer to the windshield garnish molding.
  7. Connect the electrical connector.
  8. Inspect the spot lamp for proper operation.

Spot Lamp Travel Adjustment (Impala RPO 7X6, 7X7)

  1. Loosen the spot lamp bracket clamp bolt.
  2. Grasp the spot lamp. Slowly rotate the spot lamp inboard until the shaft contacts the parkstop position.
  3. Rotate the spot lamp slowly outboard to 5 degrees past the vertical position in order for the backstop to be in motion and the outer tube shaft to rotate.
  4. Tighten the bracket clamp bolt sufficiently, in order to prevent the outer shaft tube from rotating while the spotlamp is moving between the stop positions.
  5. Rotate the spot lamp head inboard to the parkstop position in order to prevent the spot lamp from coming in contact with the body components.
  6. Position the parkstop of the shaft in order to rotate the spot lamp on its axis, clearing the nearest body components by 13-0.5 mm (0.50-0.02 in).
  7. Tighten the bracket clamp screw when the parkstop has been set, in order to prevent rotation of the spot lamp shaft. Tighten: Tighten the spot lamp bracket clamp bolt to 6 N.m (53 lb in).
  8. Adjust the spot lamp head clamping bolt, in order to easily rotate the spot lamp (120 degrees) in any adjustable position between the parkstop and the backstop positions. The total motion of the spot lamp is approximately 90 degrees. Tighten: Tighten the spot lamp head clamping bolt to 2.5 N.m (22 lb in).
  1. Open the rear compartment.
  2. Remove the rear compartment lamp using a small flat-bladed tool to release the retaining tabs.
  3. Remove the bulb from the rear compartment lamp socket.
  1. Install the bulb to the rear compartment lamp socket.
  2. Install the rear compartment lamp, pressing into place until full seated.
  3. Close the rear compartment.

Exterior Lamps

The exterior lighting system consists of the following components

  1. Headlamp switch
  2. Turn signal/multifunction switch
  3. Brake pedal position sensor
  4. Body control module (BCM)
  5. Ambient light sensor
  6. DRL PCB relay
  7. Low beam PCB relay
  8. High beam PCB relay
  9. Park lamp PCB relay
  10. Fog lamp PCB relay
  11. Low beam headlamps
  12. High beam headlamps
  13. Park lamps
  14. Tail lamps
  15. License lamps
  16. Marker lamps
  17. Turn signal lamps
  18. Stop lamps
  19. Center high mounted stop lamp (CHMSL)
  20. Backup lamps
  21. Front fog lamps

Low Beam Headlamp Operation

The low beam headlamps may be turned ON in 3 different ways

  1. When the headlamp switch in the HEAD position for normal operations
  2. When the headlamp switch is 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

Battery voltage is applied at all times to the coil and switch sides of the LOW BEAM PCB Relay located in the underhood fuse block. When the headlamp switch is placed in the HEAD position, ground is applied through headlamps ON switch signal circuit to the body control module (BCM), signaling the headlamps ON request. In response to this signal, the BCM applies ground through the headlamp low beam relay control circuit energizing the low beam relay. With the relay energized, battery voltage is applied through the switch side of the relay, the left and right low beam fuses, and the low beam supply voltage circuits illuminating the low beam headlamps.

High Beam Headlamp Operation

Battery voltage is applied at all times to the coil and switch sides of the HIGH BEAM PCB Relay located in the underhood fuse block. When the headlamp dimmer switch is placed in the high beam position, the headlamp dimmer switch signal circuit to the BCM is pulled low signaling the headlamp high beam request. In response to this signal, the BCM applies ground through the high beam relay control circuit energizing the high beam relay. With the high beam relay energized, battery voltage is applied through the switch side of the relay, the left and right high beam fuses, and the high beam supply voltage circuits illuminating the high beam headlamps. At the same time the BCM sends a serial data message to the instrument panel cluster (IPC) requesting the IPC to illuminate the high beam indicator.

Flash to Pass (FTP)

When the turn signal/multifunction switch handle is pulled toward the driver, the FTP switch is active and the flash to pass switch signal circuit to the BCM is pulled low signaling the flash to pass request. The BCM then turns ON the high beam headlamps, as described above, until the turn signal/multifunction switch handle is released. If the low beam headlamps were ON during FTP operation, they will remain ON.

Daytime Running Lamps (DRL) and Automatic Lamp Control (ALC)

The low beam headlamps are used for DRL operation at a reduced intensity. The DRLs will operate only while the engine is running and the headlamp switch is in the AUTO position. When the DRLs are ON, no other exterior lamps such as the parking lamps, tail lamps, etc. will be on when the DRL are being used. The instrument panel will not be illuminated either.

DRL operation is determined by the ambient light sensor and controlled by the body control module (BCM). The ambient light sensor is a light-sensitive transistor used to monitor outside lighting conditions. The BCM provides a 5-volt reference signal to the sensor. The sensor will vary this voltage signal between 0.2 and 4.9 volts depending on outside lighting conditions. The BCM monitors the ambient light sensor signal circuit to determine if outside lighting conditions are correct for either DRL or ALC operation. When the BCM determines the conditions are met for DRL operation, it applies ground to the DRL relay control circuit energizing the DRL PCB Relay. With the relay energized, battery voltage is applied through the switch side of the relay, the DRL 1 fuse, a resistor wire to the DRL 2 fuse, both low beam headlamp fuses, and the low beam supply voltage circuits illuminating the headlamps at a reduced intensity. Any function or condition that turns on the headlamps will cancel DRL operation.

When the BCM detects low light conditions, it will turn OFF the daytime running lamps and turn ON the low beam headlamps as described above in Low Beam Headlamp Operation. The BCM will also turn ON the low beam headlamps in daylight conditions when the windshield wipers are turned ON.

Park, Tail, Marker and License Lamps

The park, tail, license, and marker lamps are turned ON when the headlamp switch is placed in either the HEAD or PARK lamp positions, or anytime the automatic light control (ALC) turns the headlamps ON. When the headlamp switch is placed in the park lamp or headlamp positions, ground is applied through the signal circuit to the BCM indicating the park lamp request. In response to this signal, the BCM applies ground through the park lamp relay control circuit energizing the PARK LP PCB Relay. With the relay energized, battery voltage is applied through the switch side of the relay, both park lamp fuses, and the supply voltage circuits illuminating the park, tail marker, and license lamps.

Turn Signal Lamps

The LT T/SIG and RT T/SIG fuses located in the underhood fuse block supplies battery positive voltage to the body control module (BCM) for turn signal and hazard lamp operation. When the turn signal switch is place in either the LEFT or RIGHT position, ground is applied through the turn signal switch signal circuit to the BCM indicating the turn signal request. In response to this signal, the BCM applies a pulsating voltage to the front and rear turn signal lamps supply voltage circuits cycling the lamps ON and OFF. The BCM also sends a message via to the instrument panel cluster (IPC) to cycle the turn signal indicator ON and OFF depending on the position of the turn signal switch.

Hazard Lamps

The hazard flashers may be activated in any power mode. When the hazard switch is placed in the ON position, ground is applied through the hazard switch signal circuit to the body control module (BCM) indicating the hazard lamps ON request. In response to this signal, the BCM applies a pulsating voltage to all front and rear turn signal lamps supply voltage circuits cycling the lamps ON and OFF. The BCM also sends a serial data message to the instrument panel cluster (IPC) to cycle both turn signal indicators ON and OFF.

Stop Lamps

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.

The LT T/SIG and RT T/SIG fuses located in the underhood fuse block are also used by the body control module (BCM) for stop lamp operation.

The brake pedal position sensor is used to sense the action of the driver application of the brake pedal. The body control module (BCM) provides both, a 5-volt reference voltage and low reference to the brake pedal position sensor. The position sensor provides an analog voltage signal back to the BCM that will increase as the brake pedal is applied. When the brake pedal is applied, the BCM will then apply battery voltage to the left and right stop lamp supply voltage circuits and the center high mounted stop lamp (CHMSL) supply voltage circuit illuminating the stop lamps. At the same time the BCM signals the transmission control module (TCM) and the engine control module (ECM) that the brakes are applied.

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.

Backup Lamps

Battery voltage from the CHMSL/BCK-UP fuse is supplied to the body control module (BCM) for backup lamp operation. When the gear selector is placed in to the REVERSE position, the powertrain control module (PCM) sends a serial data message to the BCM indicating that the gear selector is in the reverse position. The BCM then applies battery voltage to the backup lamp supply voltage circuit illuminating the left and right backup lamps. The engine may need to be running for the backup lamps to function.

Front Fog Lamps

Battery voltage is applied at all times to the coil and switch sides of the FOG LAMP PCB Relay located in the underhood fuse block. When the fog lamp switch is turned ON, ground is applied through the fog lamp switch signal circuit to the body control module (BCM) indicating the fog lamp request. In response to this signal, the BCM applies ground to the fog lamp relay control circuit energizing the FOG LP PCB Relay. With the relay energized, battery voltage is applied through the switch side of the relay, the FOG LAMPS fuse, and the fog lamp supply voltage circuits illuminating the fog lamps. At the same time the BCM sends a message via serial data to the instrument panel cluster (IPC) requesting that the fog lamp indicator be illuminated.

Battery Rundown Protection/Inadvertent Power

The BCM controls the lighting system through circuits that enable the exterior lamp functions of the park lamps, the head lamps, the fog lamps, and the interior lamps. The BCM opens these enabling circuits 10 minutes after the ignition switch is turned OFF with no lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this time period, the timer resets for another 10 minutes.

The interior lighting consist of two groups; lamps that may not be manually dimmed (Interior Lamps) and lamps that may be dimmed (Interior Lamps Dimming).

The first group listed below includes lamps that may not be dimmed

  1. Left and right I/P courtesy lamps
  2. Dome lamp (Coupe)
  3. Dome/reading lamp (Sedan)
  4. Left and right vanity mirror lamps
  5. Reading lamp assembly (w/ 9C1, 9C3)
  6. Inside rearview mirror lamps
  7. Rear compartment courtesy lamp

Interior Lamps Features

The interior lamps system features the following functions

  1. An illuminated entry feature that illuminates the courtesy lamps when entering the vehicle or activating the remote keyless entry system.
  2. An illuminated exit feature that illuminates the courtesy lamps when the ignition key has been removed from the ignition.
  3. An inadvertent power feature that supplies voltage to all interior lamps after the ignition is turned OFF. The inadvertent power feature will deactivate all interior lamps after 10 minutes to prevent battery rundown.
  4. A theater dimming feature that will slowly dim the interior lamps from full brightness to OFF.
  5. An lamp switch assembly that illuminates the courtesy lamps.
  6. Individual switches for control of each interior lamp that is not illuminate with the interior lamp switch.

Courtesy Lamps

When the driver door is opened, ground is applied through the door latch door open switch and the left front door open switch signal circuit to the BCM indicting the door open position. Or, when either one of the passenger doors is opened, ground is applied through the door latch door open switch and the passenger door open switch signal circuit to the BCM indicating the door open position. Once a door open signal is received, the BCM will apply battery voltage from the INT LIGHTS fuse through the courtesy lamp supply voltage circuits illuminating the lamps listed below

  1. Left and right I/P courtesy lamps
  2. Dome lamp (Coupe)
  3. Dome/reading lamp (Sedan)

Courtesy Lamps Manual Operation

The courtesy lamps can be manually turned ON by the IP dimmer switch. When the dimmer switch is placed in the DOME position, ground is applied through the dimmer switch and the courtesy lamp switch ON signal circuit to the BCM indicating the courtesy lamps ON request. In response to this signal, the BCM then applies battery positive voltage from the INT LIGHTS fuse through the courtesy lamp supply voltage circuits illuminating the courtesy lamps listed above. The courtesy lamps ON operation of the dimmer switch will override any BCM operation of the interior lamps already in progress.

Keyless Entry Interior Illumination

When the remote function actuator transmitter is used to unlock the doors, the BCM receives a door-unlock signal. The BCM must have inputs that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF, and all the doors are closed. The BCM will then illuminate the courtesy lamps and will remain illuminated for approximately 25 seconds after the door is closed. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the RUN or START position, the BCM will turn OFF the courtesy lamps immediately.

Courtesy/Illuminated Exit

The illuminated exit feature will activate the courtesy lamps when the key IN input of the BCM transitions from an active state to an inactive state (removing the ignition key). When the key is removed from the ignition, the key IN input to the BCM becomes inactive. The BCM will illuminate the courtesy lamps for approximately 25 seconds.

Theater Dimming

The theater dimming feature that will slowly dim the interior lamps from full brightness to OFF. The following actions will over ride the theater dimming feature causing the courtesy lamps to deactivate immediately if no other BCM function commands the courtesy lamps ON

  1. A transition from active to inactive of the interior lamps switch, turning OFF the interior lamps switch
  2. A LOCK command from the remote keyless entry system
  3. A last door closed locking function, locking and closing all the doors

I/P Compartment Lamp

The BCM supplies battery positive voltage from the INT LTS/PNL DIM fuse through the inadvertent power courtesy lamps circuit to the IP compartment lamp. When the IP compartment is opened, the IP compartment lamp switch closes to ground and the lamp illuminates.

Rear Compartment Lamp

The BCM supplies battery positive voltage from the INT LTS/PNL DIM fuse through the inadvertent power courtesy lamps circuit to the rear compartment lamp. When the rear compartment is opened, the rear compartment lamp switch closes to ground and the lamp illuminates.

Dome/Reading Lamps

The dome/reading lamp is a duel purpose lamp that can be illuminated two different ways. First, the lamp can be turned ON during courtesy lamp operation as described above. Second, the lamps can be turned ON individually for reading lamp operation by the lamp switch. The BCM supplies battery voltage from the INT LTS/PNL DIM fuse through the inadvertent power courtesy lamp circuit to the dome/reading lamp for reading lamp operation only.

Sunshade Vanity Mirror Lamps

The BCM supplies battery voltage from the INT LTS/PNL DIM fuse through the inadvertent power courtesy lamps circuit to the left and right vanity mirror lamps. When the vanity mirror cover on the sunshade is opened, the vanity mirror lamp switch is closed to ground and the lamp illuminates.

Interior Lamps Dimming

The second interior lighting group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination, LED illumination and incandescent lamps.

  1. Headlamp switch
  2. Instrument panel cluster (IPC)
  3. Driver window switch
  4. Driver door lock switch
  5. Outside rearview mirror switch
  6. Front passenger window switch
  7. Front passenger door lock switch
  8. Radio
  9. HVAC control module
  10. Driver information center (DIC) switch
  11. Steering wheel controls

When the ignition switch is turned to the RUN position, the instrument panel cluster (IPC), radio VF display, and the HVAC control assembly turns ON at maximum brightness. When the headlamp switch is in the PARK or HEADLAMP ON position, all incandescent and LED back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. The dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The BCM supplies a voltage reference through the I/P dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the I/P lamps supply voltage circuits and the LED dimming supply circuit to all related interior lamps, illuminating them to the desired level of brightness.

Battery Rundown Protection / Inadvertent Power

The BCM controls the lighting system through circuits that enable the exterior lamp functions of the park lamps, the head lamps, the fog lamps, and the interior lamps. The BCM opens these enabling circuits 10 minutes after the ignition switch is turned OFF with no lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this time period, the timer resets for another 10 minutes.

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views -- Index
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Accessory Wiring Junction Block Replacement
• Inside Rearview Mirror Replacement
• Driver Information Display Switch Replacement
• Steering Wheel Control Switch Assembly Replacement
• Radio Replacement
• Front Side Door Window Switch Replacement (Impala)
• Door Lock Switch Replacement (Impala)
• Checking Aftermarket Accessories
• Brake Warning Indicator Malfunction
• Turn Signal Multifunction Switch Replacement
• Fastener Caution
• Instrument Panel Upper Trim Panel Replacement
• Radiator Air Upper Baffle and Deflector Replacement
• Halogen Bulb Warning
• Lifting and Jacking the Vehicle
• Front Fender Liner Replacement
• Rear Compartment Lid Inner Panel Trim Replacement
• Rear Seat Back Cushion Replacement (Impala)
• Power Distribution Schematics
• DTC B1395
• Brake Pedal Position Sensor Calibration
• Brake Pedal Position Sensor Replacement
• Fastener Tightening Specifications
• Fog Lamp Aiming
• Spot Lamp Travel Adjustment (Impala RPO 7X6, 7X7)