Diagnostic Aids
WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
The defogger indicator has its own feed circuit. If this circuit is open the defogger indicator will be inoperative but the defogger will operate.
The defogger relay control circuit and the defogger indicator circuit share the same ground circuit. An open in this circuit will cause the defogger and the defogger indicator to be inoperative.
Defogger Inoperative - Rear Window
| Step - |
Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Defogger Schematics Connector End View Reference: Stationary Windows Connector End Views |
|||
| 1 | Did you review the Rear Window Defogger Description and Operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Stationary Windows |
| 2 |
|
Go to Step 4 | Go to Step 3 |
| 3 | Does the defogger grid warm? | Go to Step 12 | Go to Step 11 |
| 4 | Command the defogger relay ON and OFF, by depressing the defogger switch. Do you hear a click when you command the defogger relay ON and OFF? |
Go to Step 6 | Go to Step 5 |
| 5 |
|
Go to Step 14 | Go to Step 10 |
| 6 | Depress the defogger switch to the ON position. Does the defogger grid warm? |
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 7 |
| 7 |
|
Go to Step 17 | Go to Step 8 |
| 8 | Test the defogger grid ground circuit for an open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 18 | Go to Step 9 |
| 9 | Test the defogger grid supply voltage circuit for an open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 18 | - |
| 10 | Test the defogger relay control circuit for an open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 18 | Go to Step 11 |
| 11 | Test the defogger switch ground circuit for an open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 18 | Go to Step 13 |
| 12 | Test the defogger indicator supply voltage circuit for an open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 18 | Go to Step 13 |
| 13 | Inspect for a poor connection at the harness connector of the defogger switch. 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 18 | Go to Step 15 |
| 14 | Inspect for a poor connection at the defogger relay connector. 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 18 | Go to Step 16 |
| 15 | Replace the defogger switch. Refer to Rear Window Defogger Switch Replacement . Did you complete the replacement? |
Go to Step 18 | - |
| 16 | Replace the defogger relay. Refer to Relay Replacement (Within an Electrical Center)
or Relay Replacement (Attached to a Wire Harness)
in Wiring Systems. Did you complete the replacement? |
Go to Step 18 | - |
| 17 | Replace the rear glass. Refer to Window Replacement - Liftgate
in Body Rear End. Did you complete the replacement? |
Go to Step 18 | - |
| 18 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 3 |