Component Tests and General Diagnostics

1. Check Fuses 4, 15, and 16.
2. If Fuse 16 is open, check CKT 1040 for a short to ground.
3. Check Rear Window Defogger Grid for opens.
4. Check that G203, G301 and G304 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 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 General Troubleshooting Procedures). Diagnostic Aids
^ Refer to System Diagnosis. System Diagnosis - Rear Window Defogger & Heated Mirrors (SSE & SSEI Models)