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For 1990-2009 cars only

Auxiliary Blower Motor Inoperative Body Type VIN 6

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The auxiliary blower motor is inoperative in all speed positions from both the front and rear controls.

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Place the front auxiliary blower motor switch in each speed position.

Does the auxiliary blower motor operate in any of the speed positions?

 

Go to Auxiliary Blower Motor Malfunction

Go to Step 3

3

  1. Turn ON the ignition, with the engine OFF.
  2. Place the auxiliary blower motor switch in each speed position.

Does the auxiliary blower motor operate in any of the speed positions?

--

Go to Blower Motor Malfunction

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the auxiliary blower motor connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the auxiliary blower motor supply voltage circuit and the auxiliary blower motor ground circuit.
  5. Place the auxiliary blower motor switch in the minimum speed position.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 5

5

Test the battery positive voltage circuit of the auxiliary blower motor control processor for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 6

6

Test the ground circuit of the auxiliary blower motor control processor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 7

7

Important: Ensure that the auxiliary blower motor control processor connector and the auxiliary HVAC control module connectors are connected during this step in order to avoid misdiagnosis.

  1. Place the auxiliary blower motor switch in any position except OFF.
  2. Measure the frequency from the auxiliary blower motor speed control circuit of the auxiliary HVAC control module to a good ground.

Does the frequency measure near the specified value?

35 Hz

Go to Step 12

Go to Step 8

8

  1. Turn OFF the ignition.
  2. Disconnect the auxiliary HVAC control module.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the auxiliary blower motor speed control circuit of the auxiliary HVAC control module to a good ground.

Does the voltage measure near the specified value?

8-12.5 V

Go to Step 10

Go to Step 9

9

Test the auxiliary blower motor speed control circuit of the auxiliary HVAC control module for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 12

10

Test the auxiliary blower motor speed control circuit of the auxiliary 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?

--

Go to Step 17

Go to Step 13

11

Inspect for poor connections at the harness connector of the auxiliary blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

12

Inspect for poor connections at the harness connector of the auxiliary blower motor control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

13

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?

--

Go to Step 17

Go to Step 16

14

Replace the auxiliary blower motor. Refer to Auxiliary Blower Motor Replacement in Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

--

Go to Step 17

--

15

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

Did you complete the replacement?

--

Go to Step 17

--

16

Replace the auxiliary HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 17

--

17

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2

Auxiliary Blower Motor Inoperative Body Type VIN 3

Test Description

  1. The auxiliary system will not operate with the primary system in the DEFROST position.

Step

Action

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The auxiliary blower motor is inoperative in all blower motor switch positions.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

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 primary mode switch on the HVAC control module to the floor 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 either of the speed positions?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

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 7

4

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

Does the test lamp illuminate?

Go to Step 5

Go to Step 7

5

Test the ground circuit of the auxiliary blower motor for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

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 10

Go to Step 8

7

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 10

Go to Step 9

8

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

Did you complete the replacement?

Go to Step 10

--

9

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

Did you complete the replacement?

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3