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 - 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 in each speed position?

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Go to Step 4

Go to Blower Motor Malfunction

When the A/C is ON, does the customer concern occur?

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Go to Step 5

Go to Step 7

Important:: The ambient air temperature must be above 3°C (38°F).

1. Start the engine.
2. Place the blower motor switch in the maximum speed position.
3. Place the mode switch in the VENT position.
4. Place the A/C request switch in the MAX position.
5. Place temperature switch in the coldest position.

Does the A/C compressor operate?

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Go to Step 6

Go to HVAC Compressor Clutch Does Not Engage

Perform the refrigerant system performance test. Refer to Air Conditioning (A/C) System Performance Test .

Did you find and correct the condition?

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Go to Step 18

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 drive shaft of the air temperature actuator rotate?

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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 Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Test the ignition 3 voltage circuit of the 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 18

Go to Step 10

Test the low reference circuit of the 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 door control circuit of the air temperature actuator for an open, a high resistance, a short to ground, 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 18

Go to Step 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 air temperature 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 within the specified values with a smooth transition between cold and hot?

0 V at cold

12 V at hot

Go to Step 13

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 in Wiring Systems.

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 in Wiring Systems.

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 Air Temperature 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 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