Component Tests and General Diagnostics

Glass, Frames and Mechanisms

Component Tests

Grid Wire Test

1. Using a bright lamp inside the vehicle, inspect the wire grid from the exterior. A broken grid wire appears as a brown spot.

2. Run the engine at idle. Set the heated rear window switch to ON. The heated rear window indicator should come on.

3. Working from the interior of the vehicle with a voltmeter, contact the broad red-brown stripes of the heated rear window positive lead to battery side and the negative lead to ground side. The meter should read 10-13 volts. A lower voltage reading indicates a loose ground connection.

4. Contact a good ground point with the negative lead of the meter. The voltage reading should not differ.

5. With the negative lead of the meter grounded, touch each grid line of the heated rear window at its midpoint with the positive lead. A reading of approximately 6 volts indicates the line is good. A reading of zero volts indicates the line is broken between the midpoint and the B+ side of the grid line. A reading of 12 volts indicates the circuit is broken between the midpoint of the grid line and ground.