Test Description
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step will determine if one or more blower speeds are inoperative.
- 3: This step determines if the HVAC control module and blower motor control processor are attempting to control the blower motor speed.
- 5: The measured voltage on the blower speed control circuit should steadily increase from 0 V to 8.0 V as the blower speed is adjusted from the minimum speed position to the maximum speed position.
Blower Motor Malfunction
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor operates in at least one, but not all, speed positions. |
||||
| 1 | Did you perform the HVAC Diagnostic System Check? | - | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Automatic |
| 2 |
|
- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 |
|
- | Go to Step 8 | Go to Step 4 |
| 4 | Test the battery positive voltage circuit and ground circuit of the blower motor control processor for high resistance. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 14 | Go to Step 5 |
| 5 |
IMPORTANT:
The blower motor control processor and HVAC control module connectors must be connected to correctly perform the test.
|
0-8.0 V | Go to Step 7 | Go to Step 6 |
| 6 | Test the blower motor speed control circuit for an short to voltage. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 14 | Go to Step 10 |
| 7 | Test the blower motor speed signal circuit for an short to voltage, open or short to ground. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 14 | Go to Step 9 |
| 8 | Inspect for poor connections at the harness connector of the 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 14 | Go to Step 11 |
| 9 | Inspect for poor connections at the harness connector of the 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 14 | Go to Step 12 |
| 10 | 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 14 | Go to Step 13 |
| 11 | Replace the blower motor. Refer to Blower Motor Replacement
in Heating, Ventilation and Air Conditioning. Did you complete the replacement? |
- | Go to Step 14 | - |
| 12 | Replace the blower motor control processor. Refer to Blower Motor Control Processor Replacement . Did you complete the replacement? |
- | Go to Step 14 | - |
| 13 |
IMPORTANT:
Perform the recalibration procedure for the HVAC control module. Replace the HVAC control module. Refer to HVAC Control Module Replacement .Did you complete the replacement? |
- | Go to Step 14 | - |
| 14 | Operate the system in order to verify the repair. Did you correct the condition? |
- | System OK | Go to Step 2 |