B106B

B106B - Rear Defrost Control Circuit Low

For a complete wiring diagram, refer to.

Theory of Operation

When the rear defogger button is pressed, the A/C heater control sends a signal to the totally integrated power module through the CAN C interior bus. When the totally integrated power module receives the rear defrost ON signal from the A/C heater control, the TIPM sends voltage to the rear window defogger through the rear window defogger control output circuit.

• When Monitored: With ignition ON.

• Set Condition: If the rear window defogger output in the A/C heater control turned OFF and the TIPM detects the rear window defogger control circuit is either short to ground or open.






• This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Refer to HVAC System Test, ATC for stored DTC test procedures.

Test Step 1 - Test Rear Window Defogger Control Circuit for a Short to Ground

• Turn the ignition OFF.

• Disconnect the TIPM harness connector.

• Measure the resistance between ground and the rear window defogger relay control circuit in the TIPM harness connector.

Is the resistance more than 10k ohms?

Yes

• Go to Test Step 2.

No

• Repair the rear window defogger control circuit for a short to ground. Reinstall the original rear window defogger relay.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior

Test Step 2 - Test Rear Window Defogger Control Circuit for an Open

• Disconnect the body side harness connector.

• Measure the resistance of the rear window defogger control circuit between the body side harness connector and the TIPM harness connector.

Is the resistance less than 5.0 ohms?

Yes

• Go to Test Step 3.

No

• Repair the rear window defogger control circuit for an open.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior

Test Step 3 - Test Rear Window Defogger Control Circuit for Voltage

• The test lamp must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

• Connect the TIPM harness connector.

• Turn the ignition ON.

• Turn the rear window defogger ON.

• Measure the voltage of the rear window defogger control in the body side harness connector.

Does the test lamp illuminate brightly?

Yes

• Test the liftgate harness for kinked, broken or pinched wires between the liftgate side harness connector and the rear window defogger connector, and repair any obvious problems. If OK, replace the liftgate window glass.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior

No

• Replace the totally integrated power module.

• Perform the Body Verification Test. Refer to => Non-DTC Based Diagnostics. Body Interior