Test Description
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The number below refers to the step number on the diagnostic table.
- 4: The blower motor parameter must be commanded ON before an OFF command will function.
Blower Motor Always On
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The blower motor operates with the HVAC controls in the OFF position. |
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| 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 | With a scan tool observe the Blower Motor PWM Speed parameter in the Heating and Air Conditioning data list. Does the scan tool indicate that the Blower Motor PWM Speed parameter is near the specified value? |
0% | Go to Step 4 | Go to Step 6 |
| 4 |
|
- | Go to Step 6 | Go to Step 5 |
| 5 | Inspect for poor connections at the harness connector of the blower motor control processor. Refer to Wiring Repairs
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 9 | Go to Step 7 |
| 6 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 9 | Go to Step 8 |
| 7 | Replace the blower motor control processor. Refer to Blower Motor Control Processor Replacement . Did you complete the replacement? |
- | Go to Step 9 | - |
| 8 |
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 9 | - |
| 9 | Operate the system in order to verify the repair. Did you correct the condition? |
- | System OK | Go to Step 2 |