Rear Window Will Not Defog
- Turn ignition off. Check 15-amp fuse in interior fuse panel. See Fig 1. Check 40-amp DEFOG fuse in underhood fuse panel, next to battery. See Fig 2. If fuse is blown, replace blown fuse and turn ignition switch on. If fuse blows again, go to next step. If fuse is okay go to step 3).
- Turn ignition off. Unplug connectors C2 and C3 from interior fuse panel. See Fig 1. Remove 40-amp DEFOG fuse from underhood fuse panel. Unplug rear defogger relay (located in left rear of luggage compartment). Unplug rear defogger switch connector. Using a DVOM, measure resistance between ground and wires listed as follows:
- Black/Yellow wire at interior fuse panel connector C2.
- Black/Yellow wire at interior fuse panel connector C3.
- Left terminal of DEFOG fuse (Black/Orange wire) at underhood fuse and relay panel.
If any resistance reading is less than 10,000 ohms, repair suspect wire short-to-ground. If all resistance readings are 10,000 ohms or greater, go to next step.
- Turn ignition off. Remove rear window defogger relay. Apply battery voltage to Black/Yellow wire terminal and ground Purple wire terminal on relay. Measure resistance between remaining 2 terminals on relay. If resistance is less than 5 ohms, test rear defogger switch. See DEFOGGER SWITCH under SYSTEM TESTING. If rear defogger switch is okay, go to next step. If resistance is 5 ohms or greater, replace relay.
- Restore wiring connections. Turn ignition off. Unplug connectors from rear window grid. Turn ignition switch and rear defogger switch to ON position. Measure voltage at Black/Blue wire at rear window defogger grid connector. If voltage reading is less than 10 volts, go to next step. If voltage is greater than 10 volts. Check rear window grid and grid ground (Black) wire for open and repair as necessary.
- Turn ignition off. Unplug connectors from defogger switch and defogger relay. Turn ignition on. Measure voltage at Black/Orange wire and Black/Yellow wire at defogger relay connector. Measure voltage at Black/Yellow wire at defogger switch connector. If voltmeter indicates battery voltage at all measurements, go to next step. If voltmeter indicates less than battery voltage, repair suspect wire.
- With rear defogger switch disconnected, measure resistance of Black wire between defogger switch connector and chassis ground. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or greater, repair Black wire.
- Turn ignition off. Unplug rear defogger relay connector and Black/Blue wire from rear window grid. Measure resistance of Black/Blue wire between relay connector and rear window grid connector. If resistance is 5 ohms or greater, repair Black/Blue wire. If resistance is less than 5 ohms, go to next step.
- With rear defogger relay and rear widow grid wires disconnected, check resistance of Black/Blue wire between relay connector and ground. If resistance is less than 10,000 ohms, repair short to ground in Black/Blue wire. If resistance is greater than 10,000 ohms, repair rear window grid or replace rear window.