Rear Window Defogger Switch Indicator Inoperative

Possible Causes are:

Inspect Junction Block fuse No. 11. Is Junction Block fuse No. 11 open? If yes, go to next step. If no, go to step 3 .
Turn ignition off. Disconnect the Temperature Control Head C1 connector. Measure the resistance of the Fused Rear Window Defog Relay Output circuit to ground (from the output side of fuse No. 11). Is the resistance less than 5 ohms? If yes, repair the Fused Rear Window Defogger Relay Output circuit for a short to ground. Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS. If no, replace the junction block fuse No. 11. Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS.
Turn ignition off. Disconnect the Temperature Control Head C1 connector. Remove the Rear Window Defogger Relay. Check connectors, clean or repair as necessary. Ensure that Junction Block fuse No. 11 is installed. Measure the resistance of the Fused rear Window Defogger Relay Output circuit from the relay output terminal to the Temperature Control Head C1 connector. Is the resistance less than 5 ohms? If yes, replace the Temperature Control Head (AZC or manual). Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS. If no, repair the open Fused Rear Window Defogger Relay Output circuit. Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS.