Schematic Reference: HVAC Schematics

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

1

Important: Both left (driver) and right (passenger) air temperature control concerns are diagnosed in this table.

Did you perform the HVAC Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

1. Turn ON the ignition, with the engine OFF.
2. Place the mode switch in the vent position.
3. Place the blower control in each speed position.

Does the blower motor operate in any speed position?

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Go to Step 3

Go to Blower Motor Inoperative

Does the blower motor operate in each speed position?

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Go to Step 4

Go to Blower Motor Malfunction

1. Place the blower motor switch in the maximum speed position.
2. Place the mode switch in the vent position.
3. Place the recirculation switches in the recirculation position and in the outside air position.

Does the recirculation door move to the correct position?

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Go to Step 5

Go to Air Delivery Improper

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

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Go to Step 14

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 23

Go to Step 7

1. Start the engine.
2. Place the blower motor 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. Observe the drive shaft of the left and right air temperature actuator.
2. Place the left and right air temperature switches from the coldest position to the warmest position.

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

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Go to Step 9

Go to Step 10

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

Did you find and correct the condition?

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Go to Step 23

Go to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning

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 in Wiring Systems.

Did you find and correct the condition?

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Go to Step 23

Go to Step 11

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 23

Go to Step 12

Test the air temperature door control circuit of the suspect 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 23

Go to Step 13

13

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 suspect air temperature door control circuit of the air temperature actuator to a good ground.
3. Place the suspect 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?

0.25 V at cold 14.7 V at hot

Go to Step 18

Go to Step 20

Test the ignition 3 voltage circuit of the HVAC control module 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 23

Go to Step 15

Test the battery positive voltage circuit of the HVAC control module 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 23

Go to Step 16

Test the OFF blower motor control circuit of the HVAC control module for 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 23

Go to Step 17

Test the ground circuit of the HVAC control module 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 23

Go to Step 20

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 23

Go to Step 19

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 23

Go to Step 21

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 23

Go to Step 22

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 23

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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 23

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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