Testing Without Scan Tool

WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: For circuit descriptions and diagrams of the rear window defogger (EBL) system, refer to SYSTEM WIRING DIAGRAMS and WIRING DIAGRAM INFORMATION .

Remove the A/C-heater control from the instrument panel.
Using a ohmmeter, check for continuity between the ground circuit cavity of the defogger switch wire harness connector and a good ground. There should be continuity. If OK, go to step 3. If not OK, repair the open circuit as required.
Check for continuity between the ground circuit terminal and the rear window defogger relay output terminal on the back of the A/C-heater control. See Fig 1. There should be momentary continuity as the defogger switch is pressed, and then no continuity. If OK, (Refer to ELECTRICAL/HEATED GLASS - DIAGNOSIS AND TESTING) . If not OK, replace the faulty A/C-heater control.

Fig 1: A/C Heater Control - Rear View

Courtesy of DAIMLERCHRYSLER CORP.

1 - A/C-HEATER CONTROL

2 - ILLUMINATION LAMP

3 - REAR DEFOGGER/BLEND DOOR CONNECTOR

4 - ILLUMINATION LAMP

5 - VACUUM MODE SELECT CONTROL

6 - BLOWER SPEED CONTROL CONNECTOR

7 - MOUNTING SCREW LOCATIONS (4)