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 number below refers to the step number on the diagnostic table.
- 5: Listen for an audible click when the Rear Defog relay operates. Command both the ON and OFF states of the rear defog relay. Repeat the commands as necessary.
Defogger Inoperative - Rear Window
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Defogger Schematics Connector End View Reference: Stationary Windows Connector End Views |
|||
| 1 | Did you perform the Defogger Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Defogger |
| 2 |
|
Go to Step 3 | Go to Step 11 |
| 3 | Connect a test lamp between the switched side of the rear window defogger grid and a good ground. Does the test lamp illuminate? |
Go to Step 4 | Go to Step 5 |
| 4 | Connect a test lamp between the switched side of the rear window defogger grid and the ground side of the rear window defogger grid. Does the test lamp illuminate? |
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 15 |
| 5 | Command the rear defog relay ON and OFF, by depressing the rear window defogger switch. Do you hear a click when you command the Rear Defog relay ON and OFF? |
Go to Step 8 | Go to Step 6 |
| 6 |
|
Go to Step 7 | Go to Step 10 |
| 7 |
|
Go to Step 13 | Go to Step 11 |
| 8 |
|
Go to Step 9 | Go to Step 16 |
| 9 |
|
Go to Step 13 | Go to Step 17 |
| 10 | Test the supply voltage circuit of the Rear Defog relay coil for an open or a short to ground. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 21 | Go to Step 14 |
| 11 | Test the control circuit of the Rear Defog relay for an open or short to voltage. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 21 | Go to Step 12 |
| 12 | Inspect for poor connections at the harness connector of the HVAC control assembly. 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 21 | Go to Step 18 |
| 13 | Inspect for poor connections at the Rear Defog relay. 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 21 | Go to Step 19 |
| 14 | Inspect for poor connections at the harness connector of the body control module (BCM). 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 21 | Go to Step 20 |
| 15 | Repair an open or high resistance in the ground circuit of the rear window defogger. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 21 | - |
| 16 | Repair an open or short to ground in the battery positive voltage circuit of the Rear Defog relay switched input. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 21 | - |
| 17 | Repair an open or a short to ground in the supply voltage circuit of the rear window defogger grid. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 21 | - |
| 18 | Replace the HVAC control assembly. Refer to HVAC Control Module Replacement (Buick)
or HVAC Control Module Replacement (Pontiac)
in HVAC Systems - Manual. Did you complete the replacement? |
Go to Step 21 | - |
| 19 | Replace the Rear Defog relay. Did you complete the replacement? |
Go to Step 21 | - |
| 20 |
IMPORTANT:
Perform the setup procedure for the BCM. Replace the BCM. Refer to Body Control Module Replacement
in Body Control System.Did you complete the replacement? |
Go to Step 21 | - |
| 21 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 2 |