Diagnostic Procedure 2
- Unplug 1-pin harness connector from control unit. Remove rear pillar finisher/cover. Using DVOM, check continuity between control unit 1-pin harness connector terminal and rear window defogger grid. See WIRING DIAGRAM . If continuity is present, go to next step. If continuity is not present, repair open in rear window defogger grid. See DEFOGGER - REAR WINDOW article.
- Insert ignition key into ignition switch. Using DVOM connected to ground, backprobe BCM harness connector terminal No. 23. Battery voltage should be present. Remove ignition key from ignition switch. Battery voltage should not be present. If voltage readings are as specified, go to next step. If voltage readings are not as specified, check and repair ignition switch circuit.
- Check all door switches. To check door switches, turn off ignition, headlight, rear window defogger and interior light. Interior light switch should be in center position. Ensure all doors and trunk lid are closed. Turn ignition on, then turn ignition off. Press rear window defogger switch more than 10 times in 10 seconds. Step light on driver's door should illuminate.
- Leave rear window defogger switch on and turn on ignition switch within 5 seconds after defogger indicator light illuminates. If defogger indicator light turns off after one second, system is okay. If defogger indicator light does not turn off, check and repair door switch circuit.