Schematic Reference: HVAC Schematics

DEFINITION: The auxiliary blower motor operates in at least one speed position.

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Important: The auxiliary blower motor only operates at MEDIUM and HIGH speed. When the auxiliary blower switch is placed in the lowest speed setting the air flow through the center console to the rear is provided by the primary blower motor. The air speed will vary depending on the front blower motor setting.

1. Turn ON the ignition, with the engine OFF.
2. Place the front mode switch in the bi-level position.
3. Place the front blower motor switch in the minimum speed position.
4. Place the auxiliary blower motor switch in the medium speed position and the maximum speed position.

Does the auxiliary blower motor operate in each speed position?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

1. Cycle the auxiliary blower switch through all speed positions:
2. Observe the Rear HVAC Fan Speed parameter in the Rear HVAC/rear seat audio (RSA) data list.

Does the Rear HVAC Fan Speed parameter change with each command?

Go to Step 4

Go to Step 8

1. Turn OFF the ignition.
2. Disconnect the harness connector of the auxiliary blower motor.
3. Turn ON the ignition, with the engine OFF.
4. Place the auxiliary blower motor switch in the maximum speed position.
5. Connect a test lamp between the auxiliary blower motor high speed control circuit and a good ground.

Does the test lamp illuminate?

Go to Step  5

Go to Step 6

1. Place the auxiliary blower motor switch in the medium speed position.
2. Connect a test lamp between the auxiliary blower motor medium speed control circuit and a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 7

Test the auxiliary blower motor high speed control circuit for an open, a high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 8

Test the auxiliary blower motor medium speed control circuit for an open, a high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 8

Inspect for poor connections at the harness connector of the auxiliary HVAC control module. Refer to Wiring Repairs and Connector Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 10

Inspect for poor connections at the harness connector of the auxiliary blower motor. Refer to Wiring Repairs and Connector Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 11

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

Did you complete the replacement?

Go to Step 12

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Replace the auxiliary blower motor. Refer to Auxiliary Blower Motor Replacement .

Did you complete the replacement?

Go to Step 12

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3