Previous, Next, Contents, Home.

Rear Window Defogger

The rear window defogger is a series of resistance elements that heat up as electrical current passes through them. One or two wires that do not heat up suggests a break in the heating element. Repair material for the element is available from an authorized Volkswagen dealer to repair the breaks as described below. An element that does not operate at all suggests that power is not reaching the heating element. Check for voltage supply to the window element and check for a good connection to ground. Refer to the current flow diagrams at the end of the section for details of the rear window defogger wiring.

To find and repair heating element breaks:
1. Wrap a small piece of aluminum foil around the negative (-) probe of a voltmeter.
2. With the heating element's wiring connected, touch the positive (+) voltmeter probe to the end of the heater element closest to the incoming voltage source.
3. With the ignition and the defogger switch on, place the foil-covered negative probe on the faulty wire near the positive side of the element and slowly slide it toward the negative side. The point at which the voltmeter deflects from zero volts to several volts is where the wire is broken.
4. Apply a strip of masking tape to either side of the break, leaving the break exposed. Apply the repair material over the break and allow it to dry for one hour at room temperature. Remove the tape and retest the wire.

Previous, Next, Contents, Home.