Schematic Reference: HVAC Schematics

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

1

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Symptoms - HVAC Systems - Manual

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 in Heating, Ventilation and Air Conditioning.

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 MAX 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 left and right air temperature actuator.
2. Place the air temperature switch from the coldest position to the warmest position.

Does the left and right air temperature actuator drive shaft rotate at all?

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Go to Step 8

Go to Step 9

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 ignition 3 voltage circuit of the suspect air temperature actuator for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs a in Wiring Systems.

Did you find and correct the condition?

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Go to Step 18

Go to Step 10

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

Did you find and correct the condition?

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Go to Step 18

Go to Step 11

Test the suspect air temperature door control circuit of the air temperature actuator for an open, high resistance, short to ground, or 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 18

Go to Step 12

12

Important: HVAC control module connector must be connected to correctly perform this test.

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

Does the voltage measure within the specified values with a smooth transition between COLD and HOT?

0-12 V

Go to Step 15

Go to Step 13

Inspect for poor connections at the harness connector of the suspect air temperature actuator. 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 18

Go to Step 14

Inspect the suspect 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 in Wiring Systems.

Did you find and correct the condition?

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Go to Step 18

Go to Step 17

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 18

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Replace the HVAC control module. Refer to HVAC Control Module Replacement .

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