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1975 Continental Headlight Issues

Hi Bill -

I own a 1975 Continental. It has 90k original miles on it and I love the car. One little problem though, if I turn on the headlights, the low beams won't work. If I switch to high beams they work but after about 5 minutes, they start flashing on and off. I can hear a relay under the dash on the passenger side, maybe above the glovebox, that clicks on and off with the lights. My tail lights and dash lights also turn off and on repeatedly. Any ideas on what that relay is? Or maybe you know of something else? Any ideas would be greatly appreciated since I am limited to daytime driving only.

Thank you!




Hi Sean -

The possibilities are numerous with these types of issues therefore some smart testing will be necessary to pinpoint the problem or problems. You don't tell us if the car is a recent purchase that came with these problems or if you have the AUTOLAMP option or not but if the tail lights, dash lights and license plate light are also flashing on and off with the headlamps it indicates that the circuit breakers in the headlamp switch are tripping off and on. This happens if the headlamp units have been replaced by newer style lights that require more power than the original design of the lighting circuit or if a circuit or circuits somehow have become grounded. In any case the breaker will open the circuit as designed to prevent melting the wires or causing a fire. Vehicles with upgraded headlamp beams may cause the h/l breaker to finally fatigue and will require relays to be added to remove the higher load through the headlamp switch in order to prevent circuit breaker cycling. The headlamp switch may also prove to be worn out and not usable as well. Another possibility is that both low beam filaments in your low beams are burnt out. This is not uncommon. You also could have two separate faults in two locations. The best way to diagnose this system for wiring problems is with the use of the correct wiring diagram and tracing the power path from the headlamp switch with the use of a 12v test light in a logical sequence to the headlamps.

The Autolamp system will be of course more complicated to diagnose if your Lincoln is so equipped. The Autolamp option and its diagnosis are explained in the factory shop manual. It is possible however that a recent repair in some area of your car could have resulted in part of the lighting circuit to accidently become grounded. This happens very often. If you can recall that these lighting issues began soon after a repair procedure was performed on your car ( body work or electrical ) I would look carefully at that area first. Some good automotive detective work along with some electrical skills and the correct wiring diagrams will be needed in order to trace the circuit properly. The above suggestions are based on some the of every day experiences that we have here at Lincoln Land with this type of problem. Keep us posted as to what you find out and if you need more information after some testing let us know.