Diagnostic Test

WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

1) INSTALL A SUBSTITUTE REAR WINDOW DEFOGGER RELAY & THEN CHECK FOR DTC B106B-REAR DEFROST CONTROL CIRCUIT LOW

Fig 1: Identifying Relay Terminals
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition on.

Verify that the EBL mode switch is off.

Turn the ignition off.

Install a substitute Rear Window Defogger Relay.

Turn the ignition on.

With the scan tool, erase HVAC DTCs.

Turn the ignition off, wait 10 seconds, and turn the ignition on.

With the scan tool, read HVAC DTCs.

Does the scan tool display: B106B-REAR DEFROST CONTROL CIRCUIT LOW?

Yes
1. Go To 2).
No
1. Replace the original Rear Window Defogger Relay in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
2) CHECK (C115) REAR WINDOW DEFOGGER RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND

Fig 2: Checking Rear Window Defogger Relay Control Circuit For Short To Ground
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Remove the substitute Rear Window Defogger Relay.

Disconnect the A/C Heater Control C1 harness connector.

Measure the resistance of the (C115) Rear Window Defogger Relay Control circuit between ground and the A/C Heater Control C1 harness connector.

Is the resistance below 10k ohms?

Yes
1. Repair the (C115) Rear Window Defogger Relay Control circuit for a short to ground. Reinstall the original Rear Window Defogger Relay.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
No
1. Go To 3).
3) CHECK (C115) REAR WINDOW DEFOGGER RELAY CONTROL CIRCUIT FOR AN OPEN

Fig 3: Checking Rear Window Defogger Relay Control Circuit For Open
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (C115) Rear Window Defogger Relay Control circuit between the Rear Window Defogger Relay connector terminal 85 in the PDC and the A/C Heater Control C1 harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Replace the A/C Heater Control in accordance with the Service Information. Reinstall the original Rear Window Defogger Relay.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
No
1. Repair the (C115) Rear Window Defogger Relay Control circuit for an open. Reinstall the original Rear Window Defogger Relay.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .