Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
- When the primary HVAC system is placed to the defrost position, the auxiliary HVAC controls are disabled.
- The auxiliary blower motor is only enabled when in medium and high speeds. When low speed is selected the primary HVAC blower forces air through the auxiliary system. The air speed will vary depending on the speed of the primary blower motor.
Air Delivery Improper - Auxiliary (VIN 3 including Envoy XUV)
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: Air does not flow correctly from the auxiliary air distribution outlets. |
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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 Step 3 | Go to Blower Motor Always On - Auxiliary (VIN 6 excluding Envoy XUV) or Blower Motor Always On - Auxiliary (VIN 3 including Envoy XUV) |
| 3 |
|
- | Go to Blower Motor Inoperative - Auxiliary (VIN 6 excluding Envoy XUV) or Blower Motor Inoperative - Auxiliary (VIN 3 including Envoy XUV) | Go to Step 4 |
| 4 | Does the auxiliary blower motor operate in each speed position? | - | Go to Step 5 | Go to Blower Motor Malfunction - Auxiliary (VIN 6 excluding Envoy XUV) or Blower Motor Malfunction - Auxiliary (VIN 3 including Envoy XUV) |
| 5 |
|
- | Go to Step 6 | Go to Step 12 |
| 6 |
|
- | Go to Step 7 | Go to Step 13 |
| 7 | Test the ground circuit of the auxiliary mode actuator 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 16 | Go to Step 8 |
| 8 |
|
|
Go to Step 10 | Go to Step 9 |
| 9 | Test the auxiliary mode door control circuit of the auxiliary mode actuator for an open, a short to ground or a short to voltage. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 16 | Go to Step 12 |
| 10 | Inspect the auxiliary mode door and the auxiliary mode actuator for the following:
Did you find and correct the condition? |
- | Go to Step 16 | Go to Step 11 |
| 11 | Inspect for poor connections at the harness connector of the auxiliary mode actuator. 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 | Inspect for poor connections at the harness connector of the auxiliary 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 15 |
| 13 | Repair the ignition 3 voltage circuit of the auxiliary mode actuator. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 16 | - |
| 14 | Replace the auxiliary mode actuator. Refer to Mode Actuator Replacement - Console . Did you complete the replacement? |
- | Go to Step 16 | - |
| 15 | Replace the auxiliary HVAC control module. Refer to HVAC Control Module 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 3 |