Test C: Rear Window Defogger Does Not Shut Off Automatically
WARNING: This page is about a different car, the 2002 Mercury Grand Marquis and 2002 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
- Turn ignition switch to LOCK position. Remove rear window defogger relay from Battery Junction Box (BJB), located at right front of engine compartment. See Figure. Measure resistance between ground and rear window defogger relay connector C1099 cavity terminal No. 86 (Gray/Light Blue wire). See Figure. See WIRING DIAGRAMS . If resistance is 10 k/ohms or less, go to next step. If resistance is greater than 10 k/ohms, go to step 3.
- Disconnect Lighting Control Module (LCM) 22-pin harness connector C2145a, located behind left center side of instrument panel. See Figure. Measure resistance between ground and rear window defogger relay connector C1099 cavity terminal No. 86 (Gray/Light Blue wire). See Figure. See WIRING DIAGRAMS . If resistance is greater than 10 k/ohms, replace LCM. See LIGHTING CONTROL MODULE under REMOVAL & INSTALLATION. If resistance is 10 k/ohms or less, repair short to ground in Gray/Light Blue wire between rear window defogger relay and LCM. After repair, clear DTC and test system for normal operation.
- Turn ignition switch to RUN position. Measure voltage between ground and rear window defogger relay connector C1099 cavity terminal No. 87 (Brown/Light Blue wire). See Figure. See WIRING DIAGRAMS . If voltage does not exist, replace rear window defogger relay. If voltage exists, repair short to power in Brown/Light Blue wire between rear window defogger relay and hidden antenna module. After repair, clear DTC and test system for normal operation.