Rear Window Antenna

With this type of antenna, two metal conductors at the very top of the glass act as the antenna for AM reception. The remaining conductors serve for FM (VHF) reception and also act as the heating wires of the rear window defroster. An antenna amplifier located under the trim of the left rear pillar compensates for the low height of this antenna system.

Behind the left rear pillar trim are:
1 – FM (VHF) antenna connection;
2 – common connection for the rear window defroster and the AM antenna;
3 – antenna amplifier.

The ground point (arrow) for the rear window defroster and rear window antenna is located on the right rear pillar. The illustration shows the pillar with the trim removed.

Rear Window Antenna Troubleshooting
PROCEDURE

Remove the trim from both rear pillars.

Check the ground connection of the rear window defroster at the right pillar. Then check the ground connection (body) of the antenna amplifier at its mounting bolt.

Carefully inspect the conductors on the rear window: is there a visible break? If so, repair it with conductive silver paint or replace the glass.

Next, perform an electrical check: disconnect the amplifier connectors and measure the voltage to ground. To do this, switch on the radio.

Voltage present: the amplifier power supply is good. No voltage: repair the open circuit.

On the same wire, measure the current between the amplifier connection and the disconnected wire.

The ammeter should show 30–50 mA. Otherwise, the antenna amplifier is not receiving power and is therefore faulty – replace it.

Next: disconnect the lower rear window defroster wire, turn on the ignition and the rear window defroster, and measure the voltage in the wire.

The wire must have battery voltage. Otherwise, the wires or the amplifier are faulty. Narrow down the fault search.

Disconnect the lower wire from the amplifier and measure the voltage with the ignition and rear window defroster switched on:
If the meter shows battery voltage, the wires are good, meaning the amplifier is faulty. Otherwise, the opposite applies.