Component Tests and General Diagnostics

1. CHECK to see that RR DEFOG and HTR-A/C Fuses are not open. If open, LOCATE and REPAIR source of overload, then REPLACE Fuse(s).
2. CHECK that grounds G200 and G403 are clean and tight.
3. CHECK that Rear Defogger Grid(s) is continuous and free from damage.
4. If Rear Window Defogger operates normally but ON Indicator fails, CHECK and REPLACE Indicator lamp if open. If lamp is OK, REPLACE HVAC Control Panel.
^ CHECK for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove GOOD in a Continuity/Voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load).
^ CHECK for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (Refer to Troubleshooting Procedures). Diagnostic Aids