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 G400 are clean and tight.
3. CHECK that Rear Defogger Grid(s) is continuous and free from damage.
4. If vehicle is not equipped with a Liftgate, then CHECK that LH/RH Door Contact Switch contacts are clean and free from obstructions.
5. If the Rear Defogger Grid(s) do not automatically shut OFF after 10 minutes, then the Solid State Time Delay Relay for the Rear Defogger Switch may have failed.
6. If the Rear Defogger Switch ON indication Light Emitting Diode (LED) does not illuminate but the Defogger Grid(s) Defog, than the (LED) may have failed.
^ 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 "Troubleshooting Procedures"). Diagnostic Aids