Component Tests and General Diagnostics

PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS
1. Make sure Engine is RUNNING when trying to activate Rear Defogger and Heated Mirrors.
2. Check for open Rear Defogger (RR DEFOG) Fuse or A/C Clutch Fuse.
3. If Rear Defogger works, but Heated Mirrors do not, check for open Heated Mirror (HTD MIR) Fuse.
4. If Central Control Module (CCM) Diagnostic Trouble Code (DTC) 22 is set, refer to Central Control Module for diagnosis. Central Control Module
5. A rare condition may occur with the Electronic A/C System only. The CCM may not recognize the Rear Defogger "ON/OFF" Switch on the first attempt. Try several times before determining if there is actually a problem.
^ 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)