Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or the heating is insufficient.

1

Important: Both the left and the right air temperature controls are diagnosed in this table.

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Observe the DTC List in Vehicle DTC Information.

Does the scan tool display any DTC B0408, B0409, B0414, B0418, B0419, or B0424?

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Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

1. Turn ON the ignition, with the engine OFF.
2. 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

Except for the blower motor speed, are all of the functions of the HVAC control module inoperative?

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Go to Step 13

Go to Step 6

Inspect the cooling system for the following conditions:

Did you find and correct the condition?

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Go to Step 22

Go to Step 7

1. Start the engine.
2. Place the blower switch in the OFF position.
3. Place the A/C request switch in the OFF position.

Does the A/C compressor operate?

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Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 8

1. Install a scan tool.
2. Observe the Driver Temp Door Position and Passenger Temp Door Position in the HVAC scan tool data list.
3. Adjust the air temperature switch.

Does the scan tool indicate the driver and passenger temp data values are within the specified parameter?

0-255 Counts

Go to Step 9

Go to Step 10

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

Did you find and correct the condition?

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Go to Step 22

Go to Heating Performance Diagnostic

Test the door control circuit of the air temperature actuator for the following conditions:

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 11

Test the ground circuit of the air temperature actuator for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 12

12

Important:: Ensure that the HVAC control module connector is connected during this step in order to avoid misdiagnosis.

1. Turn ON the ignition, with the engine OFF.
2. Measure the voltage from the door control circuit of the air temperature actuator to a good ground.
3. Place the air temperature switch from the coldest position to the warmest position.

Is the voltage measurement within the specified values with a smooth transition between cold and hot?

0 V at cold

12 V at hot

Go to Step 17

Go to Step 19

Test the ignition 1voltage circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 14

Test the battery positive voltage circuit of the HVAC control module for an open or for a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 15

Test the blower motor control OFF circuit of the HVAC control module for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 16

Test the ground circuit of the HVAC control module for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 21

Inspect for poor connections at the harness connector of the air temperature actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 18

Inspect the air temperature actuator, door and any attaching linkage for binding or a condition that prevents drive shaft rotation.

Did you find and correct the condition?

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Go to Step 22

Go to Step 20

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

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Go to Step 22

Go to Step 21

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

Did you complete the replacement?

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Go to Step 22

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Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

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Go to Step 22

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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 2