Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: Temperature variation between driver and passenger A/C or heater outlets.

Did you perform the HVAC Diagnostic System Check?

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Go to Step 4

Go to Diagnostic System Check - HVAC Systems - Automatic

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Perform the Re-Calibrating Actuators Procedure. Refer to Actuator Recalibration
4. With a scan tool, observe the current DTC list in Instrument Panel Module.

Does the scan tool display any DTCs?

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Go to Diagnostic Trouble Code (DTC) List

Go to Step 5

3

1. Place the right air temperature switch in the middle position.
2. Place the auto switch in the OFF position.
3. With a scan tool, observe the Left Temp Dr. Actual and Right Temp Dr. Actual parameters in the HVAC Door Positions data list.
4. Place the air temperature switch from the coldest position to the warmest position.

Is the operating range of the Left Temp Dr. Actual parameter near the operating range of the Right Temp Dr. Actual parameter?

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Go to Step 4

Go to Too Hot in Vehicle

1. Place the air temperature switch in the middle position until the temperature display indicates 24°C (75°F).
2. With a scan tool, observe the Right Temp Dr. Commanded parameter.
3. Place the right air temperature switch from the coldest position to the warmest position.

Did the Right Temp Dr. Actual parameter change?

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Go to Step 5

Go to Passenger HVAC Control Does Not Operate Properly

When the A/C is ON, does the customer concern occur?

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Go to Step 6

Go to Step 12

Important:: Ambient air temperature must be above 3°C (38°F).

1. Cover the sunload sensor assembly.
2. Start the engine.
3. Fully open all panel outlets.
4. Place the temperature switch in the coldest position.
5. Place the mode switch in the vent, panel position.
6. Place the blower motor switch in the maximum speed position.
7. Place the right air temperature switch assembly in the neutral position.
8. Ensure that the vent, ambient air indicator is not illuminated.

Is the difference between the right and left center panel outlet temperatures greater than the specified value?

6°C (10°F)

Go to Step 7

System OK

Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test in Heating, Ventilation and Air Conditioning.

Did you find and correct the condition?

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Go to Step 26

Go to Step 8

Inspect the air temperature sensors for proper installation. Refer to the following procedures:

Did you find and correct the condition?

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Go to Step 26

Go to Step 9

1. Install a scan tool.
2. Cover the sunload sensor assembly.
3. Start the engine.
4. Place the temperature switch in the 24°C (75°F) position.
5. Place the right air temperature switch assembly in the neutral position.
6. With a scan tool, observe the Right and Left Solar Sensor data parameters in the Instrument Panel Module Open/Short data list.

Does the scan tool indicate that the Right and Left Solar Sensor data parameters are greater than the specified value?

224 Counts

Go to Step 10

Go to Step 21

1. Uncover the sunload sensor assembly.
2. Direct a light source at the right and then the left side of the sunload sensor assembly.

Do the counts change similarly and correspond to the proper side of the sunload sensor assembly?

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Go to Step 11

Go to Step 21

1. Install a thermometer near the following air temperature sensors:

•	Upper right

•	Upper left

•	Lower right

•	Lower left

2. With a scan tool, observe the following data parameters in the Instrument Panel Module HVAC Sensor data list:

•	Right AC Duct Temp

•	Left AC Duct Temp

•	Right Htr. Duct Temp

•	Left Htr. Duct Temp

Does the scan tool indicate sensor temperatures near the thermometer temperatures within the specified range?

+3 to -3°C

(+5 to -5°F)

System OK

Go to Step 19

1. Cover the sunload sensor assembly.
2. Start the engine.
3. Fully open all panel outlets.
4. Place the temperature switch in the warmest position.
5. Place the mode switch in the floor position.
6. Place the blower motor switch in the maximum speed position.
7. Place the right air temperature switch assembly in the neutral position.

Is the difference between the right and left outlet temperatures greater than the specified value?

6°C (10°F)

Go to Step 13

System OK

Inspect the cooling system for the following conditions:

Did you find and correct the condition?

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Go to Step 26

Go to Step 14

Perform the Heating Performance Diagnostic. Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning.

Did you find and correct the condition?

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Go to Step 26

Go to Step 15

Inspect the air temperature sensors for proper installation. Refer to the following procedures:

Did you find and correct the condition?

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Go to Step 26

Go to Step 16

1. Install a scan tool.
2. Cover the sunload sensor assembly.
3. Start the engine.
4. Place the temperature switch in the 24°C (75°F) position.
5. Place the right air temperature switch assembly in the neutral position.
6. With a scan tool, observe the Right and Left Solar Sensor data parameters in the Instrument Panel Module Open/Short Data list.

Does the scan tool indicate that the Right and Left Solar Sensor data parameters are greater than the specified value?

224 Counts

Go to Step 17

Go to Step 21

1. Uncover the sunload sensor assembly.
2. Direct a light source at the right and then the left side of the sunload sensor assembly.

Do the counts change similarly and correspond to the proper side of the sunload sensor assembly?

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Go to Step 18

Go to Step 21

1. Install a thermometer near the following air temperature sensors:

•	Upper right

•	Upper left

•	Lower right

•	Lower left

2. With a scan tool, observe the following data parameters in the Instrument Panel Module HVAC Sensor data list:

•	Right AC Duct Temp

•	Left AC Duct Temp

•	Right Htr. Duct Temp

•	Left Htr. Duct Temp

Does the scan tool indicate sensor temperatures near the thermometer temperatures within the specified range?

+3 to -3°C

(+5 to -5°F)

System OK

Go to Step 19

Inspect for poor connections at the harness connector of the suspect air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 26

Go to Step 20

Test the suspect air temperature sensor resistance. Refer to Sensor Resistance Table .

Does the resistance measure near the Sensor Resistance Table value?

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Go to Step 22

Go to Step 24

Inspect for poor connections at the harness connector of the sunload sensor assembly . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 26

Go to Step 23

Inspect for poor connections at the harness connectors of the instrument panel integration module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 26

Go to Step 25

Replace the sunload sensor assembly. Refer to Sun Load Sensor Replacement .

Did you complete the replacement?

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Go to Step 26

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Replace the suspect air temperature sensor. Refer to the following procedures:

Did you complete the replacement?

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Go to Step 26

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Important: : Perform the recalibration procedure for the instrument panel integration module.

Replace the instrument panel integration module. Refer to Instrument Panel Module Replacement in Body Control System.

Did you complete the replacement?

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Go to Step 26

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Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 4