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HVAC - Automatic: Diagnosis Hummer H2 I рестайлинг

Automatic HVAC System ~4100 words

DIAGNOSTIC CODE INDEX

DTCDescription
DTC B0158, B0163, B0168, B0173, B0178, B0509, B0514, B3578 or B3583** DESCRIPTION NOT COLLECTED **
DTC B0183 or B0188B0183 05: Solar Load Sensor 1 Circuit Short to Short to Battery or Open B0183 02: Solar Load Sensor 1 Circuit Short to Ground B0188 05: Solar Load Sensor 2 Circuit Short to Short to Battery or Open B0188 02: Solar Load Sensor 2 Circuit Short to Ground
DTC B0228, B0413, B0423, B0433, B3779, or B3782B0228 02: Recirculate Position Feedback Circuit Short to Ground B0228 05: Recirculate Position Feedback Circuit Short to Battery or Open B0228 61: Recirculate Position Circuit Actuator Stuck B0413 02: Temperature Control 1 Feedback Circuit Short to Ground B0413 05: Temperature Control 1 Feedback Circuit Short to Battery or Open B0413 61: Temperature Control 1 Feedback Circuit Actuator Stuck Open B0423 02: Temperature Control 2 Feedback Circuit Short to Ground B0423 05: Temperature Control 2 Feedback Circuit Short to Battery or Open B0423 61: Temperature Control 2 Circuit Actuator Stuck B0433 02: Temperature Control 3 Feedback Circuit Short to Ground B0433 05: Temperature Control 3 Feedback Circuit Short to Battery or Open B0433 61: Temperature Control 3 Circuit Actuator Stuck B3779 02: Air Flow Control 9 Feedback Circuit Short to Ground B3779 05: Air Flow Control 9 Feedback Circuit Short to Battery or Open B3779 61: Air Flow Control 9 Circuit Actuator Stuck B3782 02: Air Flow Control 10 Feedback Circuit Short to Ground B3782 05: Air Flow Control 10 Feedback Circuit Short to Battery or Open B3782 61: Air Flow Control 10 Circuit Actuator Stuck
DTC P0530P0532: Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit P0533: Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.

DTC Descriptors

The diagnostic procedure supports the following DTCs

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Inside Air Temperature Sensor SignalB0163 02B0163 05B0163 051
Ambient Air Temperature Sensor SignalB0158 02B0158 05B0158 051
Upper Left Air Temperature Sensor SignalB0173 02B0173 05B0173 051
Upper Right Air Temperature Sensor SignalB0509 02B0509 05B0509 051
Lower Left Air Temperature Sensor SignalB0178 02B0178 05B0178 051
Lower Right Air Temperature Sensor SignalB0514 02B0514 05B0514 051
Low ReferenceB0173 05, B0158 05, B0163 05, B0509 05, B0178 05, B0514 05, B3933 05B0173 05, B0158 05, B0163 05, B0509 05, B0178 05, B0514 05, B3933 051
Right Sunload Sensor SignalB0188 02B0188 05B0188 051
1. Air Temperature Malfunction

Diagnostic Aids

ConditionDisplay
Using Scan Tool Special FunctionUpdates temperature display instantly
When the HVAC module MODE, FRONT DEFROST, and REAR DEFROST buttons are pressed simultaneously.Updates temperature display instantly
At start up with the engine off less than 2 hoursDisplays last stored temperature unless temperature has decreased. The outside air temperature reading is always instantly updated if ambient air temperature has decreased.
At start up with the engine off more than 2 hoursDisplays actual outside temperature
Vehicle speed above 32 km/h (20 mph) for a minimum of 80 secondsUpdates temperature display at a slow filtered rate
Vehicle speed above 72 km/h (45 mph)Displays actual outside temperature
Sensor ambient temperature reading is less than the last displayed valueDisplays actual outside temperature
When the ambient air decreasesUpdates temperature display rapidly

Ambient Air Temperature Display Update

Conditions for Running the DTC

The ignition is turned ON.

Conditions for Setting the DTC

The HVAC control module detects the inside air temperature sensor signal circuit is less than -36°C (-38°F) or greater than 215°C (419°F) for greater than 15 seconds.

Action Taken When the DTC Sets

The system operates using a default value.

Conditions for Clearing the DTC

  1. The DTC will become history if the HVAC control module no longer detects the condition that set the DTC.
  2. The history DTC will clear after 50 fault-free ignition cycles.

Circuit/System Testing

Ambient/Inside Air Temperature Sensor Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
  2. Test for less than 1 ohm between the low reference circuit terminal B and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, verify the appropriate scan tool Temp Sensor Voltage parameter is greater than 4.9 volts or 250 counts. If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
  4. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Temp Sensor Voltage parameter is less than 0.1 volt or 5 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, test or replace the appropriate temperature sensor.

Duct Temperature/Evaporator Temperature Sensor Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
  2. Test for less than 1.0 ohm between the low reference circuit terminal 2 and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, verify the appropriate temp sensor parameter is greater than 4.9 volts or 250 counts. If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the HVAC control module.
  4. Install a 3-amp fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool temp sensor parameter is less than 0.1 volt or 5 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, test or replace the appropriate temperature sensor.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate temperature sensor.
  2. Test for the appropriate resistance between the signal terminal A or 1 and the low reference terminal B or 2. Refer to «Sensor Resistance Table»(ref-299165-S37109316082008092200000) Sensor Resistance Table for resistance values.
  1. If not within the specified range, replace the appropriate sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Left Solar Load Sensor SignalB0183 02B0183 05B0183 05
Right Solar Load Sensor SignalB0188 02B0188 05B0188 05

Circuit Description

The following DTCs are for the left and right sunload sensors.

  1. B0183 is for the left sunload sensor.
  2. B0188 is for the right sunload sensor.

The left and right sunload sensors provide the HVAC control module with inputs as to the amount heat load the sun is placing on the interior of the vehicle. The sunload sensors are photodiodes that are sensitive to light intensity. The body control module (BCM) applies 5 volts to internal input resistors that are connected to the left and right signal circuits of the sunload sensor assembly. The BCM provides ground to the sensors through the low reference circuit. The BCM monitors the voltage drops across the sunload sensors and converts the voltage values to count values where 1 volt is approximately equal to 51 counts. As the light intensity increases, the sunload sensors allow more current to travel through the circuits and the signal voltages decrease. As the light intensity decreases, the sunload sensor allow less current to travel through the circuits and the signal voltages increase. The BCM transmits the data to the HVAC control module over the GM LAN data circuit.

The ignition is ON.

The BCM determines that the value of the sunload sensor signal is less than 5 counts (1 volt) or greater than 250 counts (5 volts).

The action taken will be for the BCM to revert to a calibrated default value.

  1. The DTC will become history if the BCM no longer detects a failure.
  2. The history DTC will clear after 100 fault-free ignition cycles.
  3. The DTC can be cleared with a scan tool.
  1. Ignition OFF, disconnect the sunload sensor harness connector at the Sunload Sensor.
  2. Test for less than 1.0 ohm of resistance between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the appropriate Sunload Sensor voltage parameter is greater than 4.9 volts or 250 counts. If less than the specified range test the appropriate signal circuit terminal A or B for a short to ground. If the circuit tests normal, replace the HVAC control module.
  4. Install a 3-amp fused jumper wire between the appropriate signal circuit terminal A or B and the ground circuit terminal C. Verify the scan tool Sunload Count parameter is less than the 0.1 volt or 5 counts. If greater than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, replace the Sunload Sensor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Recirculation 5-Volt Reference CircuitB0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0228 05B0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0228 61
Recirculation Door Position SignalB0228 02B0228 05B0228 05B0228 61
Recirculation Door Control A CircuitB0228 02B0228 05B0228 05B0228 61
Recirculation Door Control B CircuitB0228 02B0228 05B0228 05B0228 61
Recirculation Low Reference CircuitB0228 02B0228 05B0228 05B0228 61
Driver Air Temperature 5-Volt Reference CircuitB0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0413 05B0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0413 61
Driver Air Temperature Door Position SignalB0413 02B0413 05B0413 05B0413 61
Driver Air Temperature Door Control A CircuitB0413 02B0413 05B0413 05B0413 61
Driver Air Temperature Door Control B CircuitB0413 02B0413 05B0413 05B0413 61
Driver Air Temperature Low Reference CircuitB0413 02B0413 05B0413 05B0413 61
Passenger Air Temperature 5-Volt Reference CircuitB0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0423 05B0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0423 61
Passenger Air Temperature Door Position SignalB0423 02B0423 05B0423 05B0423 61
Passenger Air Temperature Door Control A CircuitB0423 02B0423 05B0423 05B0423 61
Passenger Air Temperature Door Control B CircuitB0423 02B0423 05B0423 05B0423 61
Passenger Air Temperature Low Reference CircuitB0423 02B0423 05B0423 05B0423 61
Mode 5-Volt Reference CircuitB0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B3779 05B0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B3779 61
Mode Door Position SignalB3779 02B3779 05B3779 05B3779 61
Mode Door Control A CircuitB3779 02B3779 05B3779 05B3779 61
Mode Door Control B CircuitB3779 02B3779 05B3779 05B3779 61
Mode Low Reference CircuitB3779 02B3779 05B3779 05B3779 61
Auxiliary Air Temperature 5-Volt Reference CircuitB0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0433 05B0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B0433 61
Auxiliary Air Temperature Door Position SignalB0433 02B0433 05B0433 05B0433 61
Auxiliary Air Temperature Door Control A CircuitB0433 02B0433 05B0433 05B0433 61
Auxiliary Air Temperature Door Control B CircuitB0433 02B0433 05B0433 05B0433 61
Auxiliary Air Temperature Low Reference CircuitB0433 02B0433 05B0433 05B0433 61
Auxiliary Mode 5-Volt Reference CircuitB0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B3782 05B0228 02, B0413 02, B0423 02, B0433 02, B0228 02, B3782 02 or B3779 02B3782 61
Auxiliary Mode Door Position SignalB3782 02B3782 05B3782 05B3782 61
Auxiliary Mode Door Control A CircuitB3782 02B3782 05B3782 05B3782 61
Auxiliary Mode Door Control B CircuitB3782 02B3782 05B3782 05B3782 61
Auxiliary Mode Low Reference CircuitB3782 02B3782 05B3782 05B3782 61
  1. The ignition is ON.
  2. The HVAC module is ON.

The actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position signal circuit is less than 3 counts or greater than 253 counts.

The control circuit is deactivated for the appropriate actuator.

  1. The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
  2. The history DTC will clear after 50 fault-free ignition cycles.
  1. Ignition OFF, disconnect the appropriate actuator and test for less than 1 ohm between the low reference circuit and ground. If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  2. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and ground. If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
  3. Verify the appropriate scan tool parameter is less than 4 counts. If greater than 4 counts, test the signal circuit for a short to ground. If the circuit tests normal, replace the HVAC control module.
  4. Install a 3-amp fused jumper wire between the signal circuit and the low reference circuit terminal. Verify the appropriate scan tool parameter is greater than 250 counts. If less than 250 counts, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. Ignition ON, verify that a test lamp illuminates between the ignition 3 circuit and ground. If the test lamp does not illuminate, test the ignition 3 circuit for a short to ground an open/high resistance.
  6. Install a DMM between the actuator control circuit and ground. While monitoring the DMM use the scan tool to command the appropriate actuator from one direction to the other. If the voltage on the control circuit moves from 0 volts in one direction to 5 volts in the other direction and 2.5 volts in the at rest state. If the voltage does not change, test the control circuit for an open, short to voltage or short to ground. If circuit tests normal replace the HVAC control module.
  7. If all circuits test normal, replace the actuator.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
5-Volt Reference CircuitP0530P0530
A/C Refrigerant Pressure Sensor Signal CircuitP0530P0530P0530
Low Reference CircuitP0530
  1. Engine is running.
  2. Any of the conditions for setting the DTC are met for 15 seconds.
  3. Battery voltage is between 11-18 volts.
  1. The ECM detects that the A/C pressure is less than 1 psi (0.01 volt).
  2. The ECM detects that the A/C pressure is more than 428 psi (4.92 volts).
  1. The ECM will not illuminate the malfunction indicator lamp (MIL)
  2. The ECM stores the Failure Records.
  3. The A/C compressor clutch is disabled.
  1. The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction.
  2. The DTC will become history if the ECM no longer detects a failure.

A malfunction within the refrigerant system causing high pressure can cause this DTC to set.

  1. Ignition OFF, disconnect the harness connector at the A/C pressure sensor.
  2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal 1 and ground. If greater than 1 ohm, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground. If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Verify the scan tool A/C High Side Pressure Sensor parameter is less than 428 psi. If greater than 428 psi, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Install a 3-amp fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 428 psi. If less than 428 psi, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  6. If all circuits test normal, test or replace the A/C Pressure Sensor.

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to «Checking Aftermarket Accessories»(ref-299147-S04714420442008092200000) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
  3. Verify the A/C compressor clutch turns freely and is not seized.
  4. Verify that the customer is using the correct key to enable personalization.
  5. The A/C compressor will not operate in cold outside air temperatures. Refer to «Air Temperature Description and Operation»(ref-299165-S23987229322008092200000) .
  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

Symptom List

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

  1. «Air Conditioning Compressor Malfunction»(ref-299165-S22772825322008092200000)
  2. «Blower Motor Malfunction»(ref-299165-S29512179642008092200000)
  3. «Air Temperature Malfunction»(ref-299165-S34806170852008092200000)
  4. «Leak Testing»(ref-299130-S41025427082008092200000)
  5. «Noise Diagnosis - Blower Motor»(ref-299130-S39779026432008092200000)
  6. «Noise Diagnosis - Air Conditioning (A/C) System»(ref-299130-S12876848462008092200000)
  7. «Noise Diagnosis - HVAC Module»(ref-299130-S42213090132008092200000)
  8. «Odor Diagnosis»(ref-299130-S27993283612008092200000)
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.

The following conditions must be met in order for the ECM to turn on the compressor clutch

  1. Battery voltage is between 9-18 volts
  2. Engine coolant temperature (ECT) is less than 123°C (253°F)
  3. Engine speed is less than 4,760 RPM
  4. Engine speed is more than 600 RPM
  5. A/C high side pressure is between 2929-269 kPa (425-39 psi)
  6. Throttle position is less than 100 percent
  7. Evaporator temperature is greater than 0°C (32°F)
  8. ECM does not detect excessive torque load
  9. ECM does not detect insufficient idle quality
  1. Ignition OFF, disconnect the harness connector X1 terminal A8 ground circuit terminal at the HVAC control module.
  2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal and ground. If greater than the specified, test the ground circuit for an open/high resistance.
  3. Remove the A/C compressor clutch relay.
  4. Verify that a test lamp illuminates between the relay coil B+ circuit terminal 85 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Verify that a test lamp illuminates between the relay switch B+ circuit terminal 30 and ground. If the test lamp does not illuminate, test the relay switch B+ circuit for an open/high resistance. If the A/C clutch fuse is open, test the relay switch control circuit for a short to ground. If all circuits test normal, test or replace the A/C compressor clutch.
  6. Disconnect the harness connector at the A/C compressor clutch.
  7. Ignition OFF test for less than 1.0 ohm of resistance between the A/C compressor ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  8. Connect the harness connector at the A/C compressor clutch.
  9. Connect a 10-amp fused jumper wire between the relay switch B+ circuit terminal 30 and the relay switch control circuit terminal 87. Verify the A/C compressor clutch engages. If the A/C compressor clutch does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the A/C compressor.
  10. Connect a test lamp between the relay control circuit terminal 86 and the relay coil B+ circuit terminal 85.
  11. Using a scan tool, command the A/C relay output ON and OFF. The test lamp should turn ON and OFF when changing between the commanded states. If the test lamp remains ON all the time, test for a short to ground on the control circuit connector X2 terminal 43. If the circuit tests normal, replace the ECM. If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If the circuit tests normal, replace the ECM.
  12. If all circuits test normal, test or replace the A/C compressor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Blower Motor Speed Control Circuit at the Blower Motor Control Processor1, 211, 2
Battery Positive Voltage Circuit at the Blower Motor Control Processor1
Ground Circuit of the Blower Motor Control Processor1
Blower Motor Low Reference Circuit (between motor and control processor)1
1. Blower Motor Inoperative 2. Blower Motor Always On

Be sure the blower motor housing is not shorted to a grounded surface causing the blower motor to always be on in high speed.

  1. Ignition OFF, disconnect the harness connector at the blower motor control processor connector.
  2. Test for less than 1.0 ohm of resistance between the ground circuit terminal A and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit of the blower motor speed control processor supply voltage terminal terminal C and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse (BLOWER 40-amp) fuse in the underhood BEC is open, test all components connected to the B+ circuit and replace as necessary.
  4. Connect a test lamp between the blower motor speed control circuit terminal B and the blower motor supply voltage circuit terminal C of the blower motor control processor.
  5. Turn the blower motor ON high speed and then OFF. The test lamp should dimly turn ON and OFF when changing between the commanded states. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the HVAC control module. If the test lamp is always OFF, test the speed control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  6. Ignition OFF, connect the harness connector at the blower motor control processor.
  7. Disconnect the harness connector at the blower motor.
  8. Ignition ON, verify that a test lamp illuminates between the blower motor supply voltage circuit terminal A of the blower motor and ground. If the test lamp does not illuminate, test the blower motor supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the blower motor control processor.
  9. Connect a test lamp between the blower motor supply voltage circuit terminal A and the blower motor ground circuit terminal B of the blower motor.
  10. Turn the blower motor ON high speed then to low speed. The test lamp intensity should be bright when ON high speed and very dim or out when the blower is on low speed. If the test lamp intensity is not correct, test the blower motor ground circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the blower motor control processor.
  11. If all circuits test normal, replace the blower motor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.
  1. Ignition OFF, disconnect the X2 harness connector at the auxiliary blower motor control module.
  2. Ignition OFF, test for less than 1 ohm of resistance between the ground circuit terminal 5 and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 6 and ground. If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
  4. Test for the following voltages between the signal circuit terminal 3 and ground with the auxiliary blower motor speed set at the specified levels: Off-Less than 1 volt Level 1-0.5-8.5 volts Level 2-8.5-9.5 volts Level 3-9.5-10.5 volts Level 4-10.5-11.5 volts If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module. If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
  5. Reconnect the X2 harness connector at the auxiliary blower motor control module. Disconnect the harness connector at the auxiliary blower motor.
  6. Verify that a test lamp illuminates between the B+ circuit terminal A and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the Auxiliary Blower Motor Control Module.
  7. Install a test lamp between the B+ circuit terminal A and the low reference circuit terminal B.
  8. While monitoring the test lamp, cycle the auxiliary blower motor through the various speeds. The test lamp should not illuminate with the auxiliary blower motor in the OFF position and become progressively brighter as the auxiliary blower motor speed is increased. If the test lamp is ON with the auxiliary blower motor in the OFF position, test the low reference circuit terminal B for a short to ground. If the circuit tests normal, replace the auxiliary blower motor control module. If the test lamp is always OFF, test the low reference circuit terminal B for a short to voltage or an open/high resistance. If the circuit tests normal, replace the auxiliary blower motor control module. If the test lamp does not become progressively brighter as the auxiliary blower motor speed is increased, replace the Auxiliary Blower Motor Control Module.
  9. If all circuits test normal, test or replace the auxiliary blower motor.

Install a 30A fused jumper wire between the auxiliary blower motor supply voltage terminal A and B+. Momentarily install a jumper wire between the auxiliary blower motor low reference terminal B and ground. The auxiliary blower motor should turn on.

  1. If the function does not perform as specified, replace the auxiliary blower motor.
  1. Perform the «Diagnostic System Check - Vehicle»(ref-299145-S35517489322008092200000) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(ref-299145-S33690120492008092200000) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(ref-299145-S10820546452008092200000) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Upper Left Air Temperature Sensor SignalB3578 02B3578 05B3578 05
Upper Right Air Temperature Sensor SignalB0509 02B0509 05B0509 05
Lower Left Air Temperature Sensor SignalB3583 02B3583 05B3583 05
Lower Right Air Temperature Sensor SignalB0514 02B0514 05B0514 05
Left Solar Load Sensor SignalB0183 02B0183 05B0183 05
Right Solar Load Sensor SignalB0188 02B0188 05B0188 05
1. Air Temperature Malfunction
ConditionDisplay
Using Scan Tool Special FunctionUpdates temperature display instantly
When the HVAC module MODE, FRONT DEFROST, and REAR DEFROST buttons are pressed simultaneously.Updates temperature display instantly
At start up with the engine off less than 2 hoursDisplays last stored temperature unless temperature has decreased. The outside air temperature reading is always instantly updated if ambient air temperature has decreased.
At start up with the engine off more than 2 hoursDisplays actual outside temperature
Vehicle speed above 32 km/h (20 mph) for a minimum of 80 secondsUpdates temperature display at a slow filtered rate
Vehicle speed above 72 km/h (45 mph)Displays actual outside temperature
Sensor ambient temperature reading is less than the last displayed valueDisplays actual outside temperature
When the ambient air decreases.Updates temperature display rapidly

Sun Load Sensor Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the Sunload Sensor.
  2. Test for less than 1.0 ohm between the ground circuit terminal C and ground. If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the appropriate scan tool Sunload Sensor parameter is greater than 4.9 volts or 250 counts. If less than the specified range test the appropriate signal circuit terminal A or B for a short to ground. If the circuit tests normal, replace the HVAC control module.
  4. Install a 3-amp fused jumper wire between the appropriate signal circuit terminal A or B and the ground circuit terminal C. Verify the scan tool Sunload Sensor parameter is less than the 0.1 volt or 5 counts. If greater than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, test or replace the sunload sensor.

Ambient / Inside Air Temperature Sensor Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate temp sensor.
  2. Test for less than 1 ohm between the low reference circuit terminal B and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, verify the appropriate scan tool Temp Sensor Voltage parameter is greater than 4.9 volts or 250 counts. If less than the specified range, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the HVAC control module.
  4. Install a 3-amp fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Temp Sensor Voltage parameter is less than 0.1 volt or 5 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, test or replace the appropriate temp sensor.

Duct Temperature Sensor Circuit Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate temp sensor.
  2. Test for less than 1.0 ohm between the low reference circuit terminal A and ground. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, verify the appropriate temp sensor parameter is greater than 4.9 volts or 250 counts. If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the HVAC control module.
  4. Install a 3-amp fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal B. Verify the scan tool temp sensor parameter is less than 0.1 volt or 5 counts. If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, test or replace the appropriate temp sensor.
  1. Ignition OFF, disconnect the harness connector at the appropriate temp sensor.
  2. Test for the appropriate resistance between the signal terminal A or 1 and the low reference terminal B or 2. Refer to «Sensor Resistance Table»(ref-299165-S37109316082008092200000) for resistance values.
  1. If not within the specified range, replace the appropriate sensor.

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