Rear Defogger Inoperative, But Heated Mirrors Operate Correctly
1. Connect scan tool. Turn ignition switch to RUN position. Turn rear defogger on. Using scan tool, display BCM
outputs. If rear defogger is being requested on, go to next step. If rear defogger is not being requested on, go to
step 10).
2. Ensure ignition switch is in RUN position. Remove rear defogger relay from rear junction block, located on center
right rear of passenger compartment, under rear seat. Connect test light between ground and defogger relay
harness connector terminal F3 (Brown wire). If test light illuminates, go to next step. If test light does not
illuminate, go to step 11).
3. Connect test light between ground and defogger relay harness connector terminal A2 (Red wire). If test light
illuminates, go to next step. If test light does not illuminate, go to step 12).
4. Connect test light between defogger relay harness connector terminals A2 (Red wire) and B3 (Purple wire). If test
light illuminates, go to step 13). If light does not illuminate, go to next step.
5. Disconnect rear defogger positive and negative feed bus connectors. Connect a jumper wire between defogger
relay harness connector terminals F3 (Brown wire) and A4 (White wire). Connect test light between ground and
positive feed bus connector terminal "A" (Black wire). If test light illuminates, go to next step. If test light does not
illuminate, go to step 8).
6. Connect test light between positive feed bus connector terminal "A" (Black wire) and negative feed bus connector
terminal "B" (Black wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 9).
7. Repair open in Black wire between rear defogger and ground. Recheck system operation.
8. Repair open in Purple wire between rear junction block and heated backlight antenna module. Recheck system
operation.
9. Check for proper terminal contact at rear defogger connectors. Repair as necessary. Recheck system operation.
10. Check for proper terminal contact at BCM. If terminal contact is okay, replace BCM. Recheck system operation.
11. Repair open in Brown wire between rear junction block and instrument panel junction block. Recheck system
operation.
12. Repair open in Red wire between rear junction block and underhood junction block (located in right front corner of
engine compartment, between battery and strut tower). Recheck system operation.
13. Connect test light between defogger relay harness connector terminals F3 (Brown wire) and A4 (White wire). If
test light illuminates, go to next step. If test light does not illuminate, go to step 16).
14. Reinstall defogger relay. Disconnect BCM 32-pin Pink connector C2. BCM is located behind right side of instrument
panel, near rear of glove box. Using DVOM, check voltage between ground and BCM harness connector C2
terminal A3 (White wire). If any voltage is present, go to next step. If no voltage is present, go to step 17).
15. Repair open or short to ground in White wire between rear junction block and BCM. Recheck system operation.
16. Check for poor connection at defogger relay terminals. If connections are okay, replace defogger relay. Recheck
system operation.
17. Check for proper terminal contact at BCM. If terminal contact is okay, replace BCM. Recheck system operation.
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