Test Description
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The number(s) below refer to the step number(s) on the diagnostic table.
- 2: This step tests for auxiliary blower motor operation in the OFF setting.
- 6: This step tests for a possible short to ground in the auxiliary blower motor control module control circuit.
Blower Motor Always On - Auxiliary (W/O Sunroof)
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: HVAC Schematics DEFINITION: The auxiliary blower motor is ON while the auxiliary HVAC controls are in the OFF position. |
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| 1 | Did you review the auxiliary HVAC operation and perform the necessary inspections? | - | Go to Step 2 | Go to Symptoms - HVAC Systems - Automatic |
| 2 |
IMPORTANT:
The rear auxiliary HVAC control module will only function if the front auxiliary HVAC control module is placed in the REAR position.
|
- | Go to Step 3 | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS |
| 3 |
IMPORTANT:
Place the front auxiliary HVAC control module in the REAR position. Place the rear auxiliary HVAC control module in the OFF position. Place the MODE selector in any position except AUTO. Failure to do this may result in a misdiagnosis.
|
0% | Go to Step 4 | Go to Step 11 |
| 4 | Disconnect the rear auxiliary HVAC control module. Is the blower motor operating? |
- | Go to Step 6 | Go to Step 5 |
| 5 |
|
14% | Go to Step 10 | Go to Step 8 |
| 6 | Test the rear auxiliary blower motor control module control circuit for a short to ground. Refer to CIRCUIT TESTING
and WIRING REPAIRS
. Did you find and correct the condition? |
- | Go to Step 15 | Go to Step 7 |
| 7 | Test the blower motor supply circuit for a short to voltage. Refer to CIRCUIT TESTING
and WIRING REPAIRS
. Did you find and correct the condition? |
- | Go to Step 16 | Go to Step 12 |
| 8 | Test the low reference circuit between the front auxiliary control module and the rear auxiliary control module for an open. Refer to CIRCUIT TESTING
and WIRING REPAIRS
. Did you find and correct the condition? |
- | Go to Step 16 | Go to Step 9 |
| 9 | Test the 5 volt reference circuit between the front auxiliary control module and the rear auxiliary control module for an open. Refer to CIRCUIT TESTING
and WIRING REPAIRS
. Did you find and correct the condition? |
- | Go to Step 16 | Go to Step 11 |
| 10 | Inspect for poor connections at the harness connector of the front auxiliary HVAC control module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS
and CONNECTOR REPAIRS
. 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 HVAC control module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS
and CONNECTOR REPAIRS
. Did you find and correct the condition? |
- | Go to Step 16 | Go to Step 14 |
| 12 | Inspect for poor connections at the harness connector of the auxiliary blower motor control module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS
and CONNECTOR REPAIRS
. Did you find and correct the condition? |
- | Go to Step 16 | Go to Step 15 |
| 13 | Replace the front auxiliary HVAC control module. Refer to HVAC Control Assembly Replacement - Front Auxiliary . Did you complete the replacement? |
- | Go to Step 16 | - |
| 14 | Replace the rear HVAC control module. Refer to HVAC Control Assembly Replacement - Front Auxiliary . Did you complete the replacement? |
- | Go to Step 16 | - |
| 15 | Replace the auxiliary blower motor control module. Refer to Blower Motor Processor Replacement - Auxiliary . 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 |