Circuit/System Verification

Ignition ON, observe the scan tool Rear Defog Switch parameter while pressing the Rear Defogger Switch. The reading should change between ON and OFF.
- If the reading does not change between the commanded states, refer to REAR DEFOGGER SWITCH MALFUNCTION .
Command the rear window defogger ON and OFF with the scan tool. The rear window defogger and defogger indicator should turn ON and OFF when changing between the commanded states.
- If the rear window defogger does not turn ON and OFF when changing between the commanded states, refer to REAR DEFOGGER MALFUNCTION .
- If the Defogger Indicator does not illuminate, replace the HVAC control module.