Component Tests and General Diagnostics

1. Check RR DEFOG and HTR A/C IGN Fuses by visual inspection.
2. If one or more of the grid lines do not heat.
3. If the Panel Lamp is inoperable with the Headlamp Switch in PARK or HEAD check bulb and wiring to bulb.
4. If Rear Defogger ON Indicator lights continuously or does not light at all, but Rear Defogger operates normally. replace the heater A/C Control Assembly. Refer to Control Assembly in Air Conditioning. Heating and Air Conditioning
^ Check for a broken (or partially broken) wire inside of the insulation which could cause system failure but prove GOOD in a continuity/voltage check (Refer to Troubleshooting Procedures).
^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (Refer to Troubleshooting Procedures). Diagnostic Aids