Rear Window Defogger Inoperative
NOTE:
Steps 1
- 3
confirm system operation. Indicator light illumination does not confirm system operation. It only indicates that power is available at rear window defogger relay output. If indicator light does not illuminate, check fuse No. 6 (10-amp) located in instrument panel junction block, on left end of instrument panel.
- Turn ignition switch to ON position. While monitoring instrument panel voltmeter, press rear defogger button on. If a distinct voltmeter deflection is not noted, go to step 4 . If distinct voltmeter deflection is noted, go to next step. If a severe voltmeter deflection is noted, check for short in wiring. See WIRING DIAGRAMS .
- Verify system operation by feeling glass. After 3-4 minutes of operation, a distinct difference in temperature between grid lines and adjacent clear glass should be felt. If operation is as specified, go to next step. If operation is not as specified, go to step 4 .
- Using DVOM, touch negative lead to terminal "B" and positive lead to terminal "A". See Fig 1 . If DVOM indicates 10-14 volts, system is functioning properly. If DVOM does not indicate 10-14 volts, go to next step.
- Ensure ignition switch is turned to ON position. Ensure heated glass feed wire is connected to terminal or pigtail, and ground wire is properly grounded. Ensure appropriate fuses in Power Distribution Center (PDC) and instrument panel junction block are okay. PDC is located in engine compartment near air cleaner. Instrument panel junction block is located on left end of instrument panel. See WIRING DIAGRAMS . Ensure all electrical connections are secure. Go to next step.
- If system is still inoperative, check for defective rear window defogger control switch. See DEFOGGER SWITCH TEST under COMPONENT TESTS. Check for faulty rear window defogger relay. See REAR WINDOW DEFOGGER RELAY TEST under COMPONENT TESTS. Check rear window defogger grid lines. See GRID FILAMENT TEST under COMPONENT TESTS. If rear window defogger switch, rear window defogger relay and rear window defogger grid lines check okay, problem may exist in timer circuit of Body Control Module (BCM). See appropriate BODY CONTROL MODULES article for additional information on BCM.
NOTE:
All grid lines would have to be broken or feed wire would have to be disconnected for complete system to be inoperative.