Heated Window Grid Wire

Heated Back Window Grid Wire Test, Aerostar and Explorer

1. Using a strong light inside the vehicle, visually inspect the wire grid from the outside. A broken grid wire will appear as a brown spot.

2. Run the engine on idle. Set the control switch to ON. The indicator light should come on.

3. Working inside the vehicle with a 12-volt DC voltmeter, contact the broad red-brown strips (buss bars) on the rear window. (Positive lead to battery side and negative lead to ground side. The meter should read 10-13 volts. A lower voltage reading indicates a poor connection or a low battery.

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

5. With the negative lead of the meter grounded, touch each grid line of the heated rear window at its midpoint with the positive ground lead. A reading of approximately 6 volts indicates that the line is good. A reading of zero (0) volts indicates that the line is broken between the midpoint and the B+ side of the grid line. A reading of 12 volts indicates that the circuit is broken between the midpoint of the grid line and ground.