Component Tests and General Diagnostics

Procedure

Note: Perform before beginning System Diagnosis

1. Check Fuse 3. If open, refer to Chart #2. Chart #2 HVAC Fuse 3 Blows When IGN on, or Rear Defog Turned on
2. Check Rear Defogger Grid for opens.
3. Check that grounds G200 and G310 are clean and tight.

^ Check for a broken (or partially broken) wire inside of the insulation which could cause system failure but prove "GOOD" in a continuity/voltage check. Use Test Light J 34142 whenever possible. Test lights require more current than a high impedance DVM and are more useful for detecting abnormally high resistive circuits. Some test lights have high impedances and will not be as useful in detecting resistive circuits.
^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems.