Schematic Reference: HVAC Schematics

DEFINITION: The temperature cannot be adjusted, or the cooling is insufficient during A/C operation.

1

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

Important:: In order to execute the HVAC Recalibration command, the scan tool disrupts keep alive memory (KAM) causing DTC B1652 (Loss of KAM) to be set as history.

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, perform the HVAC Recalibration command in Heating and Air Conditioning Special Functions.
4. With a scan tool, observe the current DTC list in Heating and Air Conditioning.

Does the scan tool display DTC B1340, B1341, B1343, or B1344?

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Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

Place the blower motor switch in each speed position.

Does the blower motor operate in any of the speed positions?

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Go to Step 4

Go to Blower Motor Inoperative

Does the blower motor operate in each speed position?

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Go to Step 5

Go to Blower Motor Malfunction

Important:: Ambient air temperature must be above 5°C (41°F).

1. Cover the right and left sunload sensors.
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 panel (upper) position.
6. Place the blower motor switch in the maximum speed position.
7. Ensure that the vent (outside air) indicator is not illuminated.

Does the A/C compressor operate?

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Go to Step 6

Go to HVAC Compressor Clutch Does Not Engage

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

Did you find and correct the condition?

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Go to Step 34

Go to Step 7

1. Turn ON the ignition, with the engine OFF.
2. With scan tool observe the Left Temp Dr. commanded parameter.
3. Place the air temperature switch from the coldest position to the warmest position.

Does the scan tool indicate that the Left Temp Dr. Commanded parameter change?

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Go to Step 8

Go to Step 30

1. Turn ON the ignition, with engine OFF.
2. Observe the drive shaft of the left air temperature actuator.
3. With a scan tool, command left air temperature actuator ON and OFF.

Does left air temperature actuator drive shaft rotate?

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Go to Step 10

Go to Step 9

1. Turn OFF the ignition.
2. Disconnect the left air temperature actuator.
3. Turn ON the ignition, with the engine OFF.
4. Connect a 3-amp fused jumper wire between the left air temperature door position signal circuit and the low reference circuit of the left air temperature actuator.
5. With the scan tool, observe the Left Air Temp. Dr. Actual parameter.

Does the scan tool indicate that the Left Air Temp Dr. Actual parameter is less the specified value?

10 Counts

Go to Step 10

Go to Step 23

1. Turn ON the ignition, with the engine OFF.
2. With the scan tool observe the Right Temp Dr. Commanded parameter in Heating and Air Conditioning data list.
3. Place the right air temperature switch from the coldest position to the warmest position.

Does the scan tool indicate that the Right Temp Dr. Commanded parameter change?

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Go to Step 11

Go to Step 30

1. Turn ON the ignition, with engine OFF.
2. Observe the drive shaft of the right air temperature actuator.
3. With a scan tool, command right air temperature actuator ON and OFF.

Does right air temperature actuator drive shaft rotate?

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Go to Step 14

Go to Step 12

1. Turn OFF the ignition.
2. Disconnect the right air temperature actuator.
3. Turn ON the ignition, with the engine OFF.
4. Connect a 3-amp fused jumper wire between the right air temperature door position signal circuit and the low reference circuit of the right air temperature actuator.
5. With the scan tool, observe the Right Air Temp. Dr. Actual parameter.

Does the scan tool indicate that the Right Air Temp Dr. Actual parameter is less the specified value?

10 Counts

Go to Step 13

Go to Step 25

Inspect the suspect air temperature door and the suspect air temperature actuator for the following conditions:

Did you find and correct the condition?

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Go to Step 34

Go to Step 27

Inspect each of 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 34

Go to Step 15

1. Start the engine.
2. Fully open all panel outlets.
3. Place the temperature switch in the 24°C (75°F) position.
4. Place the mode switch in the panel (upper) position.
5. Set the blower speed to illuminate 2 bars on the fan speed indicator.
6. Place the right air temperature switch in the neutral position.
7. Inspect for airflow through the inside air temperature sensor by placing a 5 cm (2 in) square piece of paper over the sensor air inlet.

Does the paper stay in place?

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Go to Step 16

Go to Step 20

1. Turn the engine OFF.
2. Install a scan tool.
3. Cover the right and left sunload sensors.
4. Start the engine.
5. Place the temperature switch in the 22°C (74°F) position.
6. Place the right air temperature switch in the neutral position.
7. With a scan tool, observe the Right and Left Solar Sensor data parameters in the Heating and Air Conditioning Open/Short Data list.

Does the scan tool indicate that the data parameters are greater than the specified value?

230  Counts

Go to Step 17

Go to Step 29

1. Uncover the right and left sunload sensors.
2. Direct the J 42220 at the right and then the left sunload sensors.

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

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Go to Step 18

Go to Step 29

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

•

Inside

•	Lower right

•	Lower left

•	Upper right

•	Upper left

2. With a scan tool, observe the following data parameters in the Heating and Air Conditioning HVAC Sensor data list.

•	Passenger Htr Duct Temp

•	Driver Htr Duct Temp

•	Driver AC Duct Temp

•	Passenger AC Duct Temp

•	Inside Air Temp

Do the scan tool temperatures differ from the thermometer temperatures by less than the specified value?

3°C (5°F)

Go to Step 19

Go to Step 21

Does the customer need to change the set temperature frequently to maintain comfort?

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Go to Air Conditioning (A/C) System Does Not Maintain Set Temperature

System OK

Inspect for a blocked or disconnected aspiration hose.

Did you find and correct the condition?

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Go to Step 34

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Inspect for poor connections at the harness connector of the suspect 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 34

Go to Step 22

Test the suspect 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 30

Go to Step 31

Test the door position signal circuit of the left air temperature actuator for an open, a high resistance, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 34

Go to Step 24

Test the low reference circuit of the left air temperature actuator for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 34

Go to Step 30

Test the door position signal circuit of the right air temperature actuator for an open, a high resistance, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 34

Go to Step 26

Test the low reference circuit of the right air temperature actuator for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 34

Go to Step 30

Inspect for poor connections at the harness connector or at the suspect air temperature actuator. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 34

Go to Step 28

Replace the suspect air temperature actuator. Refer to Air Temperature Actuator Replacement - Right Side or Air Temperature Actuator Replacement - Left Side .

Did you complete the replacement?

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Go to Step 34

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Inspect for poor connections at the harness connector of the suspect sunload 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 34

Go to Step 32

Inspect for poor connections at the harness connector of the instrument panel integration module (IPM). 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 34

Go to Step 33

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

Did you complete the replacement?

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Go to Step 34

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Replace the suspect sunload sensor. Refer to Sun Load Sensor Replacement - Left Side or Sun Load Sensor Replacement - Right Side .

Did you complete the replacement?

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Go to Step 34

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

Replace the IPM. Refer to Instrument Panel Module Replacement in Body Control System.

Did you complete the replacement?

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Go to Step 34

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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 3