Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

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

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

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 3

Go to Blower Motor Inoperative

Does the blower motor operate at the desired speeds?

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Go to Step 4

Go to Blower Motor Malfunction

Inspect the cooling system for the following conditions:

Refer to Heating Performance Diagnostic .

Did you find and correct the condition?

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Go to Step 18

Go to Step 5

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Place the mode switch in the BI-LEVEL position.
4. Place the recirculation switch in the ON position.
5. Place the A/C switch in the ON position.

Does the recirculation door move to the recirculation position?

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Go to Step 6

Go to Air Delivery Improper

Place the mode switch in the VENT or HTR positions

Does the A/C compressor operate?

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Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 7

1. Observe the drive shaft of the air temperature actuator.
2. Place the air temperature switch from the coldest position to the warmest position.

Does the air temperature actuator drive shaft rotate at all?

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Go to Step 8

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 18

Go to Step 9

Test the air temperature actuator control A and control B circuits of the air temperature actuator for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 18

Go to Step 10

1. Connect a test lamp between the air temperature actuator control A circuit and the control B circuit
2. Move the air temperature control from hot to cold

Does the test lamp illuminate with each command?

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Go to Step 13

Go to Step 11

Test the ignition 3 voltage circuit of the HVAC control module for the following:

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 18

Go to Step 12

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

Did you find and correct the condition?

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Go to Step 18

Go to Step 15

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 18

Go to Step 14

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 18

Go to Step 16

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 18

Go to Step 17

Replace the air temperature actuator. Refer to Temperature Valve Actuator Replacement .

Did you complete the replacement?

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Go to Step 18

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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 18

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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