Component Tests and General Diagnostics

Perform before beginning System Diagnosis
1. Check INST LPS Fuse, GAGES Fuse, and PWR ACC Circuit Breaker.
2. If PWR ACC Circuit Breaker is open, check CKT 340 and CKT 293 for a short to ground.
3. Check Rear Defogger for opens.
4. Check that G307, and G202 are clean and tight.
^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in 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 Diagnostic Aids. Diagnostic Aids
^ Refer to System Diagnosis. System Diagnosis - Rear Window Defogger & Heated Mirrors (SSE & SSEI Models)