Defogger Inoperative - Rear Window
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.
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 8 |
| 3 | Connect a test lamp between 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 left side of the rear window defogger grid and the right 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 10 |
| 5 |
|
Go to Step 6 | Go to Step 7 |
| 6 |
|
Go to Step 9 | Go to Step 12 |
| 7 | Test the battery positive voltage circuit of the RR DEFOG relay switched input 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 15 | Go to Step 11 |
| 8 | Inspect for poor connection 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 15 | Go to Step 13 |
| 9 | Inspect for poor connection at the RR 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 15 | Go to Step 14 |
| 10 | 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 15 | - |
| 11 | Repair a short to ground in the supply voltage circuit of the rear window defogger. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 15 | - |
| 12 | Repair an open or high resistance in the supply circuit of the rear window defogger. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 15 | - |
| 13 | Replace the HVAC Control Module. Refer to HVAC Control Module Replacement
in HVAC Systems - Automatic or HVAC Control Module Replacement
in HVAC Systems - Manual. Did you complete the replacement? |
Go to Step 15 | - |
| 14 | Replace the RR DEFOG relay. Did you complete the replacement? |
Go to Step 15 | - |
| 15 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 2 |