Auxiliary Blower Motor Malfunction W/O Sunroof
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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This step will determine if one or more blower speeds are inoperative.
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This step verifies if the rear HVAC control switch is attempting to control the auxiliary blower motor speed.
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This step verifies if the front HVAC control switch is attempting to control the auxiliary blower motor speed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics DEFINITION: The auxiliary blower motor operates in at least one, but not all, speed positions. | ||||
1 | Did you review the auxiliary HVAC operation and perform the necessary inspections? | -- | Go to Step 2 | |
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Important: The rear auxiliary HVAC control switch will only function if the front auxiliary HVAC control switch is placed in the REAR position.
Does the auxiliary blower motor operate in each speed position? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
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Important: Place the front auxiliary HVAC control module blower switch in the REAR position. Place the MODE selector in any position except AUTO. Failure to do this may result in a misdiagnosis.
Does the auxiliary blower motor PWM parameter increase within the specified range? | 0-98% | Go to Step 4 | Go to Step 5 | |
Does the auxiliary blower motor PWM parameter increase within the specified range? | 0-98% | Go to Step 7 | Go to Step 6 | |
5 | Test the 5 volt reference and low reference circuits between the front and rear HVAC control modules for an open, a short to voltage, short to ground or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 10 |
6 | Test the blower speed control circuit between the front and rear HVAC control switches for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 8 |
7 | Test the rear blower motor control module control circuit for a short to voltage, high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 11 |
8 |
Does the test lamp illuminate and change intensity? | -- | Go to Step 15 | Go to Step 11 |
9 | Inspect for poor connections at the harness connector of the rear 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 16 | Go to Step 12 |
10 | Inspect for poor connections at the harness connector of the front 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 16 | Go to Step 13 |
11 | Inspect for poor connections at the harness connector of the rear blower motor 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 16 | Go to Step 14 |
12 | Replace the rear HVAC control module. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 16 | -- |
13 | Replace the front HVAC control module. Refer to Auxiliary Heater and Air Conditioning Control Replacement - Front in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 16 | -- |
14 | Replace the rear blower motor control module. Refer to Auxiliary Blower Motor Processor Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
15 | 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 16 | -- |
16 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |
