HVAC System - Automatic Chevrolet Equinox II

Fastener Tightening Specifications

Fastener Tightening Specifications

Scheme 47

Scheme 48

Scheme 49

Scheme 50

HVAC Component Replacement Reference

HVAC Component Replacement Reference

Diagnostic Code Index

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about

1. Sun heat intensity
2. Passenger compartment temperature

The vehicle uses a sunload sensor that is integrated into one sensor assembly along with the passenger compartment temperature sensor. Low reference and signal circuits enable the sensor to operate. The sensor signal varies between 0-5 V.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

1. Ignition ON
2. The HVAC control module is ON.

Conditions for Setting the DTC

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

The system operates using a default value.

Conditions for Clearing the DTC

The sensor signal is within specified range between 0.1-4.9 V.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B10B ambient light/ sunload sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool parameter Passenger Compartment Air Temperature (Unfiltered) is less than -35°F. If -35°F or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminal 3 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If less than -35°F
5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 6.
6. Verify the scan tool parameter Passenger Compartment Air Temperature (Unfiltered) is greater than 240°F. If 240°F or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If greater than 240°F
7. Test or replace the B10B ambient light sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The air temperature sensors are a 2-wire negative temperature co-efficient thermistor. The vehicle uses the following air temperature sensors

1. Air temperature sensor - right upper
2. Air temperature sensor - right lower
3. A/C evaporator temperature sensor

A signal and low reference circuit enables the sensor to operate. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor signal voltage decreases as the resistance decreases. The sensor operates within a temperature range between -40 to +85°C (-40 to +185°F). The sensor signal varies between 0-5 V. The HVAC control module converts the signal to a range between 0-255 counts. As the air temperature increases the count value will decrease. If the HVAC control module detects a malfunctioning sensor, then the control module software will use a default air temperature value. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.

1. Ignition ON
2. The HVAC control module is ON.

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.

The system operates using a default value.

The sensor signal is within specified range between 0.1-4.9 V.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate B7 temperature sensor It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 2 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module control module. If less than 10 ohms
3. Ignition ON.
4. Verify the appropriate scan tool Temperature Sensor parameter is less than -35°C (-39°F). If -35°C (-39°F) or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminal 1 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If greater than -35°C (-39°F)
5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2.
6. Verify the scan tool temperature sensor parameter is greater than 85°C (185°F). If 85°C (185°F) or greater Ignition OFF, disconnect the harness connector at the HVAC control module, ignition ON. Test for less than 1 V between the signal circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 0.1 V
7. Test or replace the temperature sensor.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The windshield temperature and inside moisture sensor integrates the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.

This sensor assembly provides information about

1. Relative humidity level on inside windshield
2. Temperature of the inside windshield
3. Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity on the compartment side of the windshield. It also detects the temperature of the windshield surface on the compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windshield surface is not sufficient.

1. Ignition ON.
2. The HVAC control module is ON.

B018A 02, B048C 02, B048C 02 or B1395 03

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B018A 05, B048C 05, B048C 05 or B1395 07

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

1. The system will use the last valid values as default.
2. If no value is read at the time of fault, the HVAC control module uses 60% for humidity.

The condition for setting the DTC is no longer present.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/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

DTC B1395

1. Ignition OFF, disconnect the harness connector at the components listed below: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator
2. Disconnect the X3 harness connector at the K33 HVAC control module, ignition ON.
3. Test for less than 1 V between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
4. Ignition OFF.
5. Test for infinite resistance between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If less than infinite resistance Repair the short to ground on the circuit. If infinite resistance
6. Clear all DTCs, connect the X3 harness connector at the K33 HVAC control module, ignition ON.
7. Verify DTC B1395 is not set. If the DTC is set. Replace the K33 HVAC control module. If the DTC is not set.
8. Verify DTC B1395 does not set after connecting each of the components listed below, one at a time: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator If the DTC sets after connecting one of the components Replace the component that was connected immediately before the DTC set. If the DTC does not set
9. All OK.

DTC B018A, B048C, or B048F

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B160 windshield temperature and inside moisture sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 60 ohms between the low reference circuit terminal 3 and ground. If 60 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 60 ohms
3. Ignition ON.
4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K33 HVAC control module, Ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC control module. If between 4.8-5.2 V
5. Verify the scan tool parameters listed below are less than -37°C (-35°F). Windshield Temperature Passenger Compartment Humidity Sensor Temperature If -37°C (-35°F) or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminals listed below and ground: Windshield temperature sensor signal terminal 4 Passenger compartment humidity sensor temperature signal terminal 5 If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If less than -37°C (-35°F)
6. Verify the scan tool Passenger Compartment Humidity parameter is greater than 95%. If 95% or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If greater than 95%
7. Install a 3 A fused jumper wire between each signal circuit terminal listed below and the low reference circuit terminal 3 one at a time. Windshield temperature sensor signal terminal 4 Passenger compartment humidity sensor temperature signal terminal 5
8. Verify the appropriate scan tool parameter listed below is greater than 114°C (238°F). Windshield Temperature Passenger Compartment Humidity Sensor Temperature If 114°C (238°F) or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 1 V between the signal circuit terminals listed below and ground: Windshield temperature sensor signal terminal 4 Passenger compartment humidity sensor temperature signal terminal 5 If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If greater than 114°C (238°F)
9. Install a 3 A fused jumper wire between the passenger compartment humidity sensor signal circuit terminal 2 and the low reference circuit terminal 3.
10. Verify the scan tool Passenger Compartment Humidity parameter is less than 5%. If 5% or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 5%
11. Ignition OFF, disconnect the harness connector at the K33 HVAC control module, Ignition ON.
12. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
13. Test or replace the B160 windshield temperature and inside moisture sensor.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The ambient light/sunload sensor integrates the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about

1. Sun heat intensity
2. Passenger Compartment Temperature

The solar sensor is connected to ground and to the 5 V stabilized voltage supply through the HVAC control module. As the sunload increases, the sensor signal voltage also increases and vice versa. The signal varies between 1.4-4.5 V and is provided to the HVAC control module.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

1. Ignition ON
2. The HVAC Control Module is ON.

B0183 02

The input signal is out of range. The voltage is less than 0.1 V.

B0183 05

The input signal is out of range. The voltage is greater than 4.9 V.

1. The system will use the last valid values as default.
2. If no value is read at the time of fault, the HVAC control module uses 0 W/m 2 as intensity.

The condition for setting the DTC is no longer present.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/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 and all vehicle systems OFF, disconnect the harness connector at the B10B ambient light/ sunload sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 6 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 10 ohms
3. Ignition ON.
4. Verify the Sunload scan tool parameter is less than 2 W/m2. If 2 W/m2 or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminal 4 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If less than 2 W/m2
5. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the low reference circuit terminal 6.
6. Verify the scan tool parameter is greater than 20 W/m2. If 20 W/m2 or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. Test for less than 1 V between the signal circuit terminal 4 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If greater than 20 W/m2
7. Test or replace the B10B ambient light sensor.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The blower motor control module is an interface between the HVAC control module and the blower motor. The blower motor speed control from the HVAC control module, battery positive and ground circuits enable the blower motor control module to operate. The HVAC control module provides a pulse width modulation (PWM) signal to the blower motor control module in order to command the blower motor speed. The blower motor control module transfers the PWM signal into a corresponding blower motor voltage. The voltage resides between 2-13 V and changes linear to the height of the PWM signal.

1. Ignition ON.
2. The HVAC control module is ON.

B0193 01

The voltage at the HVAC control module output to the blower motor control module is always high.

B0193 06

The voltage at the HVAC control module output to the blower motor control module is always low or floating.

The blower motor is inoperative.

The condition for setting the DTC is no longer present.

Diagnostic Aids

Prior to motor replacement connect a direct independent B+ and ground to verify operation.

Inspect the motor shaft for rust or other foreign material which may prohibit proper motor operation.

If the motor operates properly please reinstall it, check for PIs or TSBs, and refer to Testing for Intermittent Conditions and Poor Connections in the appropriate Electrical Information Reference information.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/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 K8 blower motor control module. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 5 and ground. If 10 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
3. Ignition ON, verify a test lamp illuminates between B+ circuit terminal 6 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for infinite resistance between the B+ circuit terminal 6 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K8 blower motor control module. If the test lamp illuminates
4. Connect a DMM between the control circuit X1 terminal 3 and the B+ circuit terminal 6.
5. Verify the proper voltages when changing the blower speed positions. OFF 13.0 V-10.0 V HI 4.0 V-1.0 V If not within the specified range Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 1 V between the control circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If within the specified range
6. Connect the X1 harness connector at the K8 blower motor control module. Disconnect the harness connector at the M8 blower motor.
7. Connect a DMM between the control circuit terminal A and B+.
8. Verify the proper voltages when changing the blower speed positions. OFF 0 V-3.0 V HI 10.0 V-13.0 V If not within the specified range Ignition OFF, disconnect the harness connector X2 at the K8 blower motor control module. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K8 blower motor control module. If within the specified range
9. Verify a test lamp illuminates between B+ circuit terminal B and ground. If the test lamp does not illuminate Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the M8 blower motor. If the test lamp illuminates
10. All OK.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The actuators are 5-wire bi-directional electric motors that incorporate a feedback potentiometer. Low reference, 5V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 V. The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

1. Ignition ON.
2. The HVAC control module is ON.

B0228 02, B0413 02 or B374A 02

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B0228 05, B0413 05 or B374A 05

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

B1395 03

The HVAC control module detects the sensor reference voltage out of range. The reference voltage is less than 0.1 V for more than 50 ms.

B1395 07

The HVAC control module detects the sensor reference voltage out of range. The reference voltage is greater than 4.9 V for more than 50 ms.

B1395

1. The affected output will be switched off for hardware protection.
2. All actuators are deactivated.

B0228, B0413, or B374A

1. The affected output will be switched off for hardware protection.
2. The affected actuator is deactivated.

The condition for setting the DTC is no longer present.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/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, command the appropriate actuator in both directions with a scan tool. The scan tool Door Position parameter reading should be between 5-250 counts.

DTC B1395

1. Ignition OFF, disconnect the harness connector at the components listed below: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator
2. Disconnect the X3 harness connector at the K33 HVAC control module, ignition ON.
3. Test for less than 1 V between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If 1 V or greater Repair the short to voltage on the circuit. If less than 1 V
4. Ignition OFF.
5. Test for infinite resistance between the K33 HVAC control module 5 V reference circuit terminals listed below and ground: Terminal 10 X3 Terminal 20 X3 If less than infinite resistance Repair the short to ground on the circuit. If infinite resistance
6. Clear all DTCs, connect the X3 harness connector at the K33 HVAC control module, ignition ON.
7. Verify DTC B1395 is not set. If the DTC is set. Replace the K33 HVAC control module. If the DTC is not set.
8. Verify DTC B1395 does not set after connecting each of the components listed below, one at a time: B160 windshield temperature and inside moisture sensor M37 mode door actuator M46 air recirculation door actuator M6 air temperature door actuator If the DTC sets after connecting one of the components Replace the component that was connected immediately before the DTC set. If the DTC does not set
9. All OK.

DTC B0228, B0413, or B374A

1. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 1 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If less than 10 ohms
3. Ignition ON.
4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 3 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC. If between 4.8-5.2 V
5. Ignition ON.
6. Verify the scan tool Door Position parameter is less than 5 counts. If 5 counts or greater Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. Test for less than 1 V between the signal circuit terminal 2 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K33 HVAC control module. If less than 5 counts
7. Install a 3 A fused jumper wire between the signal circuit terminal 2 and the 5 V reference circuit terminal 3.
8. Verify the scan tool Door Position parameter is greater than 250 counts. If 250 counts or less Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the signal circuit terminal 2 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If greater than 250 counts.
9. Replace the actuator.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The HVAC control module supplies battery voltage to the A/C compressor. When the A/C switch is pressed, the HVAC control module provides a pulse width modulation (PWM) signal to the A/C compressor in order to command the performance of the A/C compressor. The performance of the A/C compressor is regulated according to adjusted interior temperature on the basis of characteristic lines. Therefore the HVAC control module grounds the A/C compressor with the PWM signal.

1. Ignition ON.
2. The HVAC control module is ON.

B393B 04

A PWM greater than 10% is send out but no current is read back.

B393B 0B

Measured current is above threshold of 815 mA.

B393B 04

The A/C compressor is disabled.

B393B 0B

1. The A/C compressor is disabled.
2. Output will be switched off for hardware protection.

The condition for setting the DTC is no longer present.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/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 and all vehicle systems OFF, disconnect the harness connector at the Q46 A/C compressor solenoid valve. It may take up to 2 minutes for all vehicle systems to power down.
2. Verify a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If the test lamp illuminates
3. Connect a test lamp between the control circuit terminal 1 and the B+ circuit terminal 2.
4. Verify the test lamp turns ON and OFF when Commanding the A/C Compressor Refrigerant Solenoid Valve ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the harness connector at the K33 HVAC control module, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K33 HVAC control module. If the test lamp is always ON Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If the test lamp turns ON and OFF
5. Test or replace the Q46 A/C compressor solenoid valve.

Component Testing

Static Test

1. Ignition OFF, disconnect the harness connector at the Q46 Air Conditioning Compressor Valve.
2. Test for 7-15 ohms between B+ circuit terminal 2 and control circuit terminal 1. If not within the specified range, replace the Q46 Air Conditioning Compressor Valve.
3. Test for infinite resistance between each terminal and the Q46 Air Conditioning Compressor Valve housing/case. If not the specified value, replace the Q46 Air Conditioning Compressor Valve.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The ECM supplies a 5 V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the sensor signal to the ECM to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. When pressure is high, the ECM commands the cooling fans on. When pressure is too high or too low, the ECM will not allow the activation of the A/C compressor.

Engine is running.

P0530 03 or P0532 00

The ECM detects a short to ground or open at the A/C pressure sensor signal circuit.

P0530 07 or P0533 00

The ECM detects a short to voltage at the A/C pressure sensor signal circuit.

1. The A/C compressor is disabled.
2. The ECM will illuminate the malfunction indicator lamp (MIL).

The condition for setting the DTC is no longer present.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/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 and all vehicle systems OFF, disconnect the harness connector at the B1 A/C refrigerant pressure sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference circuit terminal 1 and ground. If 10 ohms or greater Ignition OFF, disconnect the harness connector at the K20 ECM. Test for less than 2 ohms in the low reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 ECM. If less than 10 ohms
3. Ignition ON.
4. Test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground. If less than 4.8 V Ignition OFF, disconnect the harness connector at the K20 ECM control module. Test for infinite resistance between the 5 V reference circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the 5 V reference circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 ECM. If greater than 5.2 V Ignition OFF, disconnect the harness connector at the K20 ECM control module, ignition ON. Test for less than 1 V between the 5 V reference circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 ECM. If between 4.8-5.2 V
5. Verify the scan tool A/C High Side Pressure Sensor parameter is less than 4.8-5.2 V. If 4.8-5.2 V or greater Ignition OFF, disconnect the harness connector at the K20 ECM, ignition ON. Test for less than 1 V between the signal circuit terminal 3 and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V, replace the K20 ECM. If less than 4.8-5.2 V
6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 2.
7. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than.02 V. If.02 V or less Ignition OFF, disconnect the harness connector at the K20 ECM. Test for infinite resistance between the signal circuit terminal 3 and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance Test for less than 2 ohms in the signal circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 ECM. If greater than.02 V
8. Test or replace the B1 A/C refrigerant pressure sensor.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for engine control module (ECM) replacement, programming, and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

When the A/C switch is pressed, the HVAC control module sends an A/C request message to the engine control module (ECM) via serial data. The ECM grounds the A/C compressor clutch relay control circuit, which will switch the A/C compressor clutch relay. With the relay contacts closed, battery voltage is supplied to the A/C compressor clutch. The A/C compressor clutch will be activated.

1. Engine is running.
2. The HVAC control module is ON.
3. The A/C switch is active.

The ECM detects a short to ground or an open at the A/C compressor clutch relay control circuit.

The A/C compressor is inoperative.

The condition for setting the DTC is no longer present.

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/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 KR29 A/C compressor clutch relay, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground. If the test lamp does not illuminate and the circuit fuse is good Ignition OFF. Test for less than 2 ohms in the B+ circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse. If the test lamp does not illuminate and the circuit fuse is open Ignition OFF. Test for infinite resistance between the B+ circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, Test for greater than 1 ohms between the control circuit terminal A and ground. If less than 1 ohms, repair the short to ground on the circuit. If greater than 1 ohms, test or replace the KR29 A/C compressor clutch relay. If the test lamp illuminates
3. Verify a test lamp illuminates between the ignition circuit terminal 85 and ground. If the test lamp does not illuminate Replace the X50A underhood fuse block. If the test lamp illuminates
4. Connect a test lamp between the ignition circuit terminal 85 and the control circuit terminal 86.
5. Verify the test lamp turns ON and OFF when commanding the A/C compressor clutch ON and OFF with a scan tool. If the test lamp is always OFF Ignition OFF, disconnect the harness connector at the K20 ECM, ignition ON. Test for less than 1 V between the control circuit and ground. If 1 V or greater, repair the short to voltage on the circuit. If less than 1 V Ignition OFF. Test for less than 2 ohms in the control circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, replace the K20 ECM. If the test lamp is always ON Ignition OFF, disconnect the harness connector at the K20 ECM. Test for infinite resistance between the control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K20 ECM. If the test lamp turns ON and OFF
6. Verify a test lamp does not illuminate between the control circuit terminal 87 and ground. If the test lamp illuminates Repair the short to voltage on the circuit. If the test lamp does not illuminate
7. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the Q2 A/C compressor clutch.
8. Test for less than 10 ohms between the Q2 A/C compressor clutch ground circuit terminal B and ground. If 10 ohms or greater Ignition OFF. Test for less than 2 ohms in the ground circuit end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, repair the open/high resistance in the ground connection. If less than 10 ohms
9. Connect the harness connector at the Q2 A/C compressor clutch.
10. Ignition ON, connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
11. Verify the Q2 A/C compressor clutch is activated. If the Q2 A/C compressor clutch does not activate Ignition OFF. Test for less than 2 ohms in the control circuit terminal 87 end to end. If 2 ohms or greater, repair the open/high resistance in the circuit. If less than 2 ohms, test or replace the Q2 A/C compressor clutch. If the Q2 A/C compressor clutch activates
12. Test or replace the KR29 A/C compressor clutch relay.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Symptoms - HVAC Systems - Automatic

Note. The following steps must be completed before using the symptom tables

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs 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 «Automatic HVAC Description and Operation»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__automatic-hvac-description-and-operation) .

Visual/Physical Inspection

1. Inspect for aftermarket devices which may affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(/chevrolet/equinox/ii-2009-2015/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 may cause the symptom.
3. Verify the A/C compressor turns freely and is not seized.
4. Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
5. The A/C compressor will not operate in cold outside air temperatures.
6. The following conditions may cause window fogging: Wet carpet or mats High humidity Interior water leak Blocked A/C evaporator drain tube Maximum passenger capacity Blocked body pressure relief valves
7. Inspect the air distribution system for causes of reduced air flow: Obstructed or dirty passenger compartment air filter, if equipped Blocked or damaged air inlet or outlet vents

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. «Air Temperature Malfunction»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic)
2. «Air Delivery Improper»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic)
3. «Air Recirculation Malfunction»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic)

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 V. The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

Check the following mechanical fault sources

1. Air distribution box
2. Air distribution hoses/air distribution ducts

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References

1. Connect a test lamp between the control circuit terminal 4 and the control circuit terminal 5.
2. Verify the test lamp turns ON when commanding the actuator in each direction with a scan tool. If the test lamp remains OFF during either of the commands Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between each control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If the test lamp turns ON for each command
3. Replace the M6 Air Temperature Door Actuator.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5 V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 V. The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

Check the following mechanical fault sources

1. Air distribution box
2. Air distribution hoses/air distributing ducts

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References

1. Connect a test lamp between the control circuit terminal 4 and the control circuit terminal 5.
2. Verify the test lamp turns ON when commanding the actuator in each direction with a scan tool. If the test lamp remains OFF during either of the commands Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between each control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If the test lamp turns ON for each command
3. Replace the M37 Mode Door Actuator.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/chevrolet/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/chevrolet/equinox/ii-2009-2015/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/equinox/ii-2009-2015/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 V. The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

Check the following mechanical fault sources

1. Air distribution box
2. Air distribution hoses/air distribution ducts

Schematic Reference

HVAC Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
2. «Connector Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
4. «Wiring Repairs»(/chevrolet/equinox/ii-2009-2015/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References

1. Connect a test lamp between the control circuit terminal 4 and the control circuit terminal 5.
2. Verify the test lamp turns ON when commanding the actuator in each direction with a scan tool. If the test lamp remains OFF during either of the commands Ignition OFF, disconnect the harness connector at the K33 HVAC control module. Test for infinite resistance between each control circuit and ground. If less than infinite resistance, repair the short to ground on the circuit. If infinite resistance, replace the K33 HVAC control module. If the test lamp turns ON for each command
3. Replace the M46 Air Recirculation Door Actuator.

Perform the Diagnostic Repair Verification after completing the repair.

1. «HVAC Component Replacement Reference»(/chevrolet/equinox/ii-2009-2015/remont/automatic-hvac-system/#hvac-system-automatic__hvac-component-replacement-reference)
2. «Control Module References»(/chevrolet/equinox/ii-2009-2015/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for HVAC control module replacement, programming and setup

Actuator Recalibration

Note. Do not adjust any controls on the HVAC control module while the HVAC control module is self-calibrating. If interrupted, improper HVAC performance will result.

When replacing the HVAC control module it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC control module be sure to perform the following

1. Place the ignition switch to the OFF position.
2. Disconnect the scan tool.
3. Install the HVAC control module.
4. Connect all previously disconnected components.
5. Ignition ON.
6. Wait 40 s for the HVAC control module to self-calibrate.
7. Verify that no DTCs have set as current DTCs.

When replacing the HVAC actuator it will be necessary to allow the HVAC control module to perform a calibration process. When installing the HVAC actuator be sure to perform one of the following

Preferred Method (with Scan Tool)

1. Clear all DTCs.
2. Place the ignition switch in the OFF position.
3. Install the HVAC actuator.
4. Connect all previously disconnected components.
5. Start the vehicle.
6. With the scan tool, initiate the HVAC Actuators re-calibration feature of the Remote Heater and Air Conditioning Control Module Special Functions menu.
7. Verify that no DTCs have set as current DTCs.

Alternate Method (without Scan Tool)

1. Clear all DTCs.
2. Place the ignition switch to the OFF position.
3. Install the HVAC actuator.
4. Connect all previously disconnected components.
5. Remove the HVAC control module fuse for a minimum of 10 s.
6. Install the HVAC control module fuse.
7. Ignition ON.
8. Wait 40 s for the HVAC control module to self-calibrate.
9. Verify that no DTCs have set as current DTCs.

Scheme 51

Heater and Air Conditioning Control Replacement (Equinox)

Scheme 52

Heater and Air Conditioning Control Replacement (Terrain)

Scheme 53

Air Inlet Valve Actuator Replacement

Scheme 54

Mode Valve Actuator Replacement

Scheme 55

Mode Control Cam Replacement

Scheme 56

Temperature Valve Actuator Replacement

Scheme 57

Duct Air Temperature Sensor Replacement - Upper

Scheme 58

Duct Air Temperature Sensor Replacement - Lower

Scheme 59

Ambient Air Temperature Sensor Replacement

Scheme 60

Sun Load Temperature Sensor Replacement

Scheme 61

Blower Motor Control Module Replacement

Automatic HVAC Description and Operation

The air temperature and the air delivery description and operation are divided into 8 areas

1. HVAC Control Components
2. Air Speed
3. Air Delivery
4. Heating and A/C Operation
5. Recirculation Operation
6. Automatic Operation
7. Engine Coolant
8. A/C Cycle

HVAC Control Components

Radio/HVAC Control

The Radio/HVAC control contains all switches, which are required to control the functions of HVAC and serve as interface between the operator and the HVAC control module. The selected values are passed to the HVAC control module via LIN-Bus.

HVAC Control Module

The HVAC control module is a GMLAN device that interfaces between the operator and the HVAC system to maintain and control desired air temperature and air distribution settings. The battery positive voltage circuit provides power that the HVAC control module uses for keep alive memory. If the battery positive voltage circuit loses power, all HVAC DTCs and settings will be erased from keep alive memory. The body control module (BCM), which is the vehicle mode master, provides a device ON-Signal. The HVAC control module provides blower, air delivery mode and air temperature settings.

The HVAC control module supports the following features

Mode Actuator

The actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 V. The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

Air Temperature Actuator

The actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 V. The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

Recirculation Actuator

The actuator is a 5-wire bi-directional electric motor that incorporates a feedback potentiometer. Low reference, 5V reference, position signal, and 2 control circuits enable the actuator to operate. The control circuits use either a 0 or 12 V value to coordinate the actuator movement. When the actuator is at rest, both control circuits have a value of 0 V. In order to move the actuator, the HVAC control module grounds one of the control circuits while providing the other with 12 V. The HVAC control module reverses the polarity of the control circuits to move the actuator in the opposite direction. When the actuator shaft rotates, the potentiometers adjustable contact changes the door position signal between 0-5 V. The HVAC control module uses a range of 0-255 counts to index the actuator position. The door position signal voltage is converted to a 0-255 count range. When the module sets a commanded, or targeted, value, one of the control circuits is grounded. As the actuator shaft rotates the changing position signal is sent to the module. Once the position signal and the commanded value are the same, the module removes power and ground from the control circuits.

Blower Motor Control Processor

The blower motor control processor controls the speed of the blower motor by increasing or decreasing the voltage drop on the ground side of the blower motor. The HVAC control module provides a low side pulse width modulation (PWM) signal to the blower motor control processor via the blower motor speed control circuit. As the requested blower speed increases, the HVAC control module increases the amount of time that the speed signal is modulated to ground. As the requested blower speed decreases, the HVAC control module decreases the amount of time that the signal is modulated to ground.

Duct Temperature Sensors

The air temperature sensors are 2-wire negative temperature co-efficient thermistors. The sensors operate within a temperature range of -40 to +85°C (-40 to +185°F). The sensors are installed in the air distribution ducts and measure the temperature of the air that streams from the ducts. The HVAC control module uses these values to calculate the mixed air flap position.

Evaporator Temperature Sensor

The evaporator temperature sensor is a 2-wire negative temperature co-efficient thermistor. The sensor operates within a temperature range of -40 to +85°C (-40 to +185°F). The sensor is installed at the evaporator and measures its temperature. If the temperature drops under 3°C (38°F), the compressor will be switched off in order to prevent a frozen evaporator.

A/C Refrigerant Pressure Sensor

The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5 V reference voltage, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be between 0.2-4.8 V. When the A/C refrigerant pressure is low, the signal value is near 0 V. When the A/C refrigerant pressure is high, the signal value is near 5 V. The engine control module (ECM) converts the voltage signal to a pressure value. When pressure is too high or too low, the ECM will not allow the A/C compressor clutch to engage.

A/C Compressor

The A/C compressor is belt driven and operates when the magnetic clutch is engaged. When the A/C switch is pressed, the HVAC control module sends an A/C request message to the ECM via CAN-Bus. Therefore the ECM grounds the A/C compressor clutch relay control circuit, which will switch the A/C compressor clutch relay. With the relay contacts closed, battery voltage is supplied to the A/C compressor clutch. The A/C compressor clutch will be activated.

Ambient Light/Sunload Sensor

The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.

This sensor assembly provides information about

1. Sun heat intensity
2. Passenger compartment temperature

The solar sensor is connected to ground and to a 5 V stabilized voltage supply through the HVAC control module. As the sunload increases, the sensor signal voltage also increases and vice versa. The signal varies between 1.4-4.5 V and is provided to the HVAC control module.

The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0-5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Air Speed

The blower control switch is part of the Radio/HVAC control. The selected value of the blower switch position is sent to the HVAC control module via LIN-Bus.

The blower motor control module is an interface between HVAC control module and blower motor. The blower motor control module regulates supply voltage and ground circuits to blower motor. The HVAC control module provides a PWM signal to the blower motor control module in order to command the desired blower motor speed. The blower motor control module supplies battery voltage to the blower motor and uses the blower motor ground as a low side control to adjust the blower motor speed. The voltage amounts between 2-13 V and changes linear to the height of the PWM signal.

Air Delivery

The HVAC control module controls the distribution of air by the use of recirculation and mode actuator. The modes that may be selected are

1. Defrost
2. Defog
3. Panel
4. Floor

The desired air distribution mode can be selected with the air distribution switches at the Radio/HVAC control. The Radio/HVAC control delivers the values to the HVAC control module via LIN-Bus. The HVAC control module controls the air distribution actuator so that it drives the flap to the calculated position. Depending on the position of the flap, air is distributed through various ducts leading to the outlets in the dash. Turning the mode flap to the defrost position, the HVAC control module will move the recirculation actuator to outside air, reducing window fogging. When defrost is selected, the blower motor will be activated, regardless of the coolant temperature. The HVAC control module enables a high volume of air delivered to the front defrost vents. A/C is available in all modes.

The rear window defogger does not affect the HVAC system.

Heating and A/C Operation

The purpose of the heating and A/C system is to provide heated and cooled air to the interior of the vehicle. The A/C system will also remove humidity from the interior and reduce windshield fogging. Regardless of the temperature setting, the following can affect the rate that the HVAC system can achieve the desired temperature

1. Recirculation actuator setting
2. Difference between inside and desired temperature
3. Blower motor speed setting
4. Mode setting

Pressing the A/C switch or AUTO switch enables the HVAC control module to request A/C compressor engagement and turn ON the A/C switch LED respectively the AUTO switch LED if the AUTO switch is pressed. The setting of the A/C Mode can be adjusted to be set to On, Off, or kept to the Last Setting when the vehicle was last shut off. This setting is made in the Configuration Settings Menu and will determine what mode the A/C will be in when the vehicle is started. The HVAC control module sends a message to the engine control module (ECM) for A/C compressor engagement. The ECM will provide a ground for the A/C compressor relay enabling it to close its internal contacts to send battery voltage to the A/C compressor clutch coil. The A/C compressor diode will prevent a voltage peak, resulting from the collapse of the magnetic field of the coil, from entering the vehicle electrical system when the compressor is disengaged.

The following conditions must be met in order to activate the A/C compressor

1. Battery voltage is between 9-18 V.
2. Engine coolant temperature is less than 124°C (255°F).
3. Engine speed is greater than 600 RPM.
4. Engine speed is less than 5 500 RPM.
5. A/C high side pressure is between 269-2 929 kPa (39-425 PSI).
6. Throttle position is less than 100%.
7. Evaporator temperature is greater than 3°C (38°F).
8. ECM does not detect immoderate torque load.
9. ECM does not detect insufficient idle quality.
10. The ambient temperature is above 1°C (34°F).

The sensor information is used by the ECM to determine the following

1. The A/C high side pressure
2. An A/C system load on the engine
3. An immoderate A/C high side pressure
4. The heat load at the A/C condenser

The air streams into the passenger compartment through the heater core and the evaporator core. The air temperature actuator drives the mixed air flap to induce the airflow. If the interior temperature should be increased, the mixed air flap is put into the position in which more air streams through the heater core. If the interior temperature should be decreased, the mixed air flap is put into the position in which more air streams through the evaporator core.

Recirculation Operation - without Heated Seats

The recirculation switch and the fresh air switch are part of the Radio/HVAC control. The selected switch position is sent to the HVAC control module via LIN-Bus. The HVAC control module controls the air intake through the recirculation actuator. The recirculation switch closes the recirculation flap in order to circulate the air within the vehicle. Through selection of the fresh air switch, the recirculation flap is opened again in order to route outside air into the vehicle.

Recirculation is only available if the defrost mode is not active. When the defrost mode is active, the recirculation actuator opens the recirculation flap and outside air is circulated to the windshield to reduce fogging.

Recirculation Operation - with Heated Seats

The recirculation switch is part of the Radio/HVAC control. The selected recirculation switch position is sent to the HVAC control module via LIN-Bus. The HVAC control module controls the air intake through the recirculation actuator. The recirculation switch closes the recirculation flap in order to circulate the air within the vehicle. Through renewed selection of the recirculation switch, the recirculation flap is opened again in order to route outside air into the vehicle.

Recirculation is only available if the defrost mode is not active. When the defrost mode is active, the recirculation actuator opens the recirculation flap and outside air is circulated to the windshield to reduce fogging.

Automatic Operation

In automatic operation, the HVAC control module maintains the comfort level inside of the vehicle by controlling the A/C compressor clutch, the blower motor, the air temperature actuators, mode actuator and recirculation actuator. Personalized settings for auto fan speed, air conditioning mode, and remote start auto heat seats are available in the Configuration Settings Menu.

To put the HVAC system in automatic mode, the following is required

1. The auto switch must be activated.
2. The air temperature switch must be in any other position than full hot or full cold position.

Once the desired temperature is reached, the blower motor, mode, recirculation and temperature actuators automatically adjust to maintain the temperature selected. The HVAC control module performs the following functions to maintain the desired air temperature

1. Monitors the following sensors: Ambient air temperature sensor Lower left air temperature sensor Upper left air temperature sensor Ambient light/sunload sensor
2. Regulate blower motor speed
3. Position the air temperature actuator
4. Position the mode actuator
5. Position the recirculation actuator
6. Request A/C operation

When the warmest position is selected in automatic operation the blower speed will increase gradually until the vehicle reaches normal operating temperature. When normal operating temperature is reached the blower stays on high speed and the air temperature actuators stays in the full heat position.

When the coldest position is selected in automatic operation the blower stays on high and the air temperature actuators stay in full cold position. The mode actuator remains in the panel position and the recirculation actuator will remain in the recirculation position.

Under cold ambient temperatures, the automatic HVAC system provides heat in the most efficient manner. The operator can select an extreme temperature setting but the system will not warm the vehicle any faster. Under warm ambient temperatures, the automatic HVAC system also provides air conditioning in the most efficient manner. Selecting an extreme cool temperature will not cool the vehicle any faster.

Note. The "High" blower setting cannot raise the blower setting past 12, and the "Low" blower preference cannot drop the blower setting below 1, but the blower setting in Auto can be in-between blower settings.

Personalized Auto Fan Speed settings of "High", "Low", and "Normal" can be selected. The factory setting is "Normal", and will control the fan speed automatically from 1 to 12 according to the vehicle air temperature sensors and preprogrammed logic. A "High" personal fan setting can increase the fan speed up to 1 blower setting. A "Low" personal fan setting can decrease the fan speed 1 blower setting across a range of vehicle conditions.

Engine Coolant

Engine coolant is the essential element of the heating system. The thermostat controls the normal engine operating coolant temperature. The thermostat also creates a restriction for the cooling system that promotes a positive coolant flow and helps prevent cavitation.

Coolant enters the heater core through the inlet heater hose, in a pressurized state. The heater core is located inside the HVAC control module. The ambient air drawn through the HVAC control module absorbs the heat of the coolant flowing through the heater core. Heated air is distributed to the passenger compartment, through the HVAC control module, for passenger comfort. Opening or closing the air temperature flap controls the amount of heat delivered to the passenger compartment. The coolant exits the heater core through the return heater hose and recirculates back to the engine cooling system.

A/C Cycle

Refrigerant is the key element in an air conditioning system. R-134a is presently the only Environmental Protection Agency approved refrigerant for automotive use. R-134a is a very low temperature gas that can transfer the undesirable heat and moisture from the passenger compartment to the outside air.

The compressor builds pressure on the vapor refrigerant. Compressing the refrigerant also adds heat to the refrigerant. The refrigerant is discharged from the compressor, through the discharge hose, and forced to flow to the condenser and then through the balance of the A/C system. The A/C system is mechanically protected with the use of a high pressure relief valve. If the A/C refrigerant pressure sensor fails or if the refrigerant system becomes restricted and refrigerant pressure continued to rise, the high pressure relief will pop open and release refrigerant from the system.

Compressed refrigerant enters the condenser in a high temperature, high pressure vapor state. As the refrigerant flows through the condenser, the heat of the refrigerant is transferred to the ambient air passing through the condenser. Cooling the refrigerant causes the refrigerant to condense and change from a vapor to a liquid state.

The condenser is located in front of the radiator for maximum heat transfer. The condenser is made of aluminum tubing and aluminum cooling fins, which allows rapid heat transfer for the refrigerant. The semi-cooled liquid refrigerant exits the condenser and flows to the Receiver/Dehydrator (R/D).

The R/D contains desiccant that absorbs moisture that may be in the refrigerant system. The R/D also acts as a storage vessel to ensure that a steady flow of liquid reaches the thermal expansion valve. The refrigerant exits the R/D and flows through the liquid line to the thermal expansion valve.

The thermal expansion valve is located at the front of dash and attaches to the evaporator inlet and outlet pipes. The thermal expansion valve is the dividing point for the high and the low pressure sides of the A/C system. As the refrigerant passes through the thermal expansion valve, the pressure on the refrigerant is lowered. The thermal expansion valve also meters the amount of liquid refrigerant that can flow into the evaporator.

Refrigerant exiting the thermal expansion valve flows into the evaporator core in a low pressure, liquid state. Ambient air is drawn through the HVAC control module and passes through the evaporator core. Warm and moist air will cause the liquid refrigerant boil inside of the evaporator core. The boiling refrigerant absorbs heat from the ambient air and draws moisture onto the evaporator. The refrigerant exits the evaporator through the suction line and back to the A/C compressor, in a vapor state, and completing the A/C cycle of heat removal. At the A/C compressor, the refrigerant is compressed again and the cycle of heat removal is repeated.

The conditioned air is distributed through the HVAC control module for passenger comfort. The heat and moisture removed from the passenger compartment will also change form, or condense, and is discharged from the HVAC control module as water.

See also:
• Evaporator Air Temperature Sensor Replacement
• 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
• Checking Aftermarket Accessories
• Instrument Panel Upper Trim Panel Replacement (Terrain)
• Fastener Caution
• Actuator Recalibration
• Instrument Panel Insulator Panel Replacement - Left Side (Terrain)
• Communication Interface Module Replacement
• Battery Negative Cable Disconnection and Connection
• Front Bumper Fascia Replacement (Terrain)
• Air Inlet Valve Actuator Replacement
• Automatic HVAC Description and Operation
• HVAC Component Replacement Reference