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July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Rear Window Defogger Stays On Continuously

WARNING: This page is about a different car, the 1997 Mercury Mountaineer and 1997 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: This test is associated with DTCs B1342, B1347 and B1345.

  1. Check DTCs

    Retrieve DTCs from GEM. See MODULE COMMUNICATIONS NETWORK article for additional information on code retrieval procedure. If no DTCs are displayed, go to next step. If DTC B1345 is displayed, go to step 4). If DTC B1347 is displayed, go to next step. If DTC B1342 is displayed, replace GEM and retest system.

  2. Check Rear Defogger Relay

    Remove rear defogger relay. Test relay. See REAR DEFOGGER RELAY under COMPONENT TESTING . Replace relay if necessary. If relay is okay, leave relay disconnected and go to next step.

  3. Check For Short To Power

    Remove fuse No. 32 from interior fuse panel. Disconnect defogger grid power harness connector at back window. Turn ignition on. Using voltmeter, measure voltage between defogger grid connector and ground. If battery voltage exists, repair short to battery voltage in Brown/Light Blue wire changing to Black wire between rear defogger relay and defogger grid connector. If battery voltage does not exist, reconnect relay and go to next step.

  4. Check RDEF_SW PID

    Monitor RDEF_SW PID while pressing rear defogger switch on and off. If RDEF_SW PID indicates ON continuously, go to step 6). If RDEF_SW PID toggles ON and OFF with switch position, go to next step.

  5. Check Orange/Yellow Wire

    Turn ignition off. Remove rear defogger relay located behind top right of instrument panel. Disconnect 18-cavity harness connector from GEM (in center of dash). Measure resistance of Orange/Yellow wire between GEM module pin No. 16 and ground. If resistance is more than 10 k/ohms, replace GEM. Clear all DTCs and retest system. If resistance is less than 10 k/ohms, repair short to ground in Orange/Yellow wire and retest system.

  6. Check RDEF_SW PID

    Disconnect rear defogger switch and monitor RDEF_SW PID. If RDEF_SW PID indicates ON continuously, go to next step. If RDEF_SW PID indicates OFF, replace rear defogger switch and retest system.

  7. Check Dark Blue/Orange Wire For Open

    Turn ignition off. Disconnect 26-pin harness connector from GEM located in center of instrument panel. Measure resistance of Dark Blue/Orange wire between rear defogger switch connector pin No. 3 and ground. If resistance is less than 10 k/ohms, replace GEM. Clear all DTCs and retest system. If resistance is greater than 10 k/ohms, repair open in Dark Blue/Orange wire.
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