Firebird V6-3.8L VIN K (1995)
Heated Glass Element: Diagnostic Trouble Code Tests and Associated Procedures
Circuit Operation
When the Ignition Switch is turned to "RUN," voltage is applied through the HVAC Fuse 3 to the Rear Defogger Switch and the Rear Defogger
Timer/Relay. When the Rear Defogger Switch is pressed, voltage is momentarily applied to the Rear Defogger Timer/Relay through CKT 292. When
voltage is applied to the Rear Defogger Timer/Relay, the Rear Defogger Timer/Relay will close the internal contacts. The internal contacts remain closed
until the defog cycle is complete or Rear Defogger Switch is pressed a second time.
When the internal contacts of the Rear Defogger Timer/Relay are closed, voltage is applied to the Rear Defogger Grid and Indicator.
The Rear Defogger Timer/Relay contains an internal timer to control the time the internal contacts are closed. When the Ignition Switch is turned to
"RUN" and the Rear Defogger Switch pressed for the first time, the defog cycle lasts 10 minutes and further operation will result in 5 minute defog
cycles. The defog cycle is reset to 10 minutes when the Ignition Switch is turned to "OFF" and back to "RUN."
System Check
System Diagnosis - Rear Window Defogger & Heated Mirrors (SSE & SSEI Models)
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Perform the System Check and refer to the Symptom Table for the appropriate diagnostic procedures. See: Symptom Related Diagnostic
Procedures/A Symptom Table - Rear Window Defogger & Heated Mirrors (SSE & SSEI Models) See: Symptom Related Diagnostic
Procedures/A Symptom Table - Rear Window Defogger & Heated Mirrors (SSE & SSEI Models)
Troubleshooting Hints
Perform before beginning System Diagnosis
1. Check HVAC Fuse 3. If open, refer to Chart #2. See: Symptom Related Diagnostic Procedures/Symptom Diagnostic Charts/Chart #2 Rear
Defogger Grid and Indicator Inoperative
2. Check Rear Defogger Grid for opens, refer to Body and Frame. See: Body and Frame
3. Check that grounds G200, G310 and G320 are clean and tight.
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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).
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Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (Refer to "Diagnostic
Aids/General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids
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Refer to System Diagnosis. See: System Diagnosis - Rear Window Defogger & Heated Mirrors (SSE & SSEI Models)
