The 1988 Firebird features headlight motors that raise and lower the headlight assemblies. If both motors are not working, the headlights will remain in a lowered position, where they cannot illuminate the road. The isolation relay, an electrical device in the engine compartment, controls both headlight motors and is the most likely cause of the motor issues. Fixing this component will most likely restore functionality to your headlight motors.
Turn off your Firebird. Open the hood and keep it propped open with the hood support rod.
Locate the isolation relay on the chassis of the Firebird near the driver's side headlight assembly. The isolation relay is near the fender side of the engine compartment and looks like a small, grey box with a wiring harness attached to the bottom.
Unplug the wiring harness from the bottom of the isolation relay. Press in on the side tabs of the harness and pull it out of the relay.
Inspect the contacts on the wiring harness for corrosion or discoloration. Scrub off a layer of corrosion with your eraser. Spread a small amount of dielectric gel over the contacts to prevent future corrosion. Plug the wiring harness back into the relay. Turn the Firebird on and test the headlight motors. If they do not come on, continue to the next step.
Connect the negative lead of a voltmeter to the negative battery terminal. Connect the positive lead of the voltmeter the wiring harness. Check that voltage is coming through the wiring harness. Replace the wiring harness if no voltage is coming through. Replace the wiring harness feeding the isolation relay if no voltage is detected. If voltage is detected, continue to the next step.
Connect the negative lead of the voltmeter to the negative battery terminal. Connect the positive lead to the wires coming out of the isolation relay. If no voltage is detected, replace the relay.
