Rear Defogger Relay Control Circuit Open/Short To Ground

Monitored & Set Condition

1. When Monitored: With the ignition On.
2. Set condition: When the BCM detects no voltage on the Rear Window Defogger Control circuit due to an open or short to ground.

Possible Causes:

• Code Active
• Relay Open Or Shorted
• Junction Block Rear Window Defogger Relay Control Short To Ground
• Junction Block Rear Window Defogger Relay Control Open
• Body Control Module

Testing

1. Turn the ignition on. With the DRBIII(R), erase DTCs. Operate the Rear Window Defogger. With the DRBIII(R), read DTCs. Does the DRBIII(R) display REAR WINDOW DEFOGGER RELAY CONTROL CIRCUIT OPEN/SHORT TO GROUND? If yes, go to next step. If no, problem is intermittent and not present at this time. Inspect the wiring and connectors and repair as necessary. Ensure the relay is completely plugged in. Perform BODY VERIFICATION TEST  .
2. Remove the Rear Window Defogger Relay from the Junction Block. Install a substitute relay in place of the Rear Window Defogger Relay. With the DRBIII(R), erase DTCs. Operate the Rear Window Defogger. With the DRBIII(R), read DTCs. Does the DRBIII(R) display REAR WINDOW DEFOGGER RELAY CONTROL CIRCUIT OPEN/SHORT TO GROUND? If yes, go to next step. If no, replace the original relay. Perform BODY VERIFICATION TEST  .
3. Ensure the remaining Junction Block connectors are reconnected. Turn the ignition off. Remove the Rear Window Defogger Relay from the Junction Block. Remove the Body Control Module from the Junction Block. Measure the resistance between ground and the Rear Window Defogger Relay Control circuit in the relay connector of the Junction Block. Is the resistance below 100.0 ohms? If yes, replace the Junction Block. Perform BODY VERIFICATION TEST  . If no, go to next step.
4. Turn the ignition off. Remove the Rear Window Defogger Relay from the Junction Block. Remove the Body Control Module from the Junction Block. Measure the resistance of the Rear Window Defogger Relay Control circuit between the Relay connector and the Junction Block - BCM connector. Is the resistance below 2.0 ohms? If yes, go to next step. If no, replace the Junction Block. Perform BODY VERIFICATION TEST  .
5. If there are no possible causes remaining, replace the Body Control Module. Perform BODY VERIFICATION TEST  .