For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 |

1. Backprobe the rear defogger switch connector C1 between terminal B (Buick/Oldsmobile) or terminal 3 (Pontiac) and ground.
2. Press the rear defogger switch.

Does the test lamp illuminate?

--

Go to Step 2

Go to Step 3

2 | Replace the rear defogger switch. Refer to Rear Window Defogger Switch Replacement . Did you complete the repair? | -- | System OK | --
3 | Test CKT 681 for an open. Is an open in CKT 681? | -- | Go to Step 4 | Go to Step 5
4 | Repair an open in CKT 681. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | System OK | --
5 | Replace the multi-function alarm module. Refer to Multi-Function Alarm Module Replacement in Keyless Entry. Did you complete the repair? | -- | System OK | --