35th Anniversary Thunderbird Registry

Headlights Flicker or operate irratically

The following information comes from discussions with people who have experienced this problem over the years and from my own experience from having it happen to me. I researched and inquired about this to come to the following conclusions.

If your headlights begin to go out at times or flicker on and off, they are showing a system flaw that seems to occur after a number of years of using the factory lighting setup. I understand there was even a technical service bulletin on the headlight switch about this. I have even heard of internal wiring getting too hot and melting contacts and wires inside switches. The diagram below shows the flow of current with the factory setup to the headlights and fog lights. Using the foglights and dim beams over time seems to be too much for the system wiring. My first suggestion to solve this problem is to stop using the foglights at all. Then I would remove and inspect the headlight switch to see if any of the contacts look darkened. Hopefully that is all you will see and it would be adviseable to replace the headlight switch. Next I would remove the lower instrument panel trim and cover below the steering wheel and the steering column trim panels and check to make sure none of the wiring has gotten too hot. The turn signal, dimmer, and wiper switch is called the multifunction switch and it may have been damaged. If everything looks okay, be relieved and replace the steering column and trim panels.

At this point, you have to decide if you will stop there or try to improve the system. If you want to improve the lighting system, my first suggestion is to rewire the foglights and ease the load on the existing wiring and switches. I used the method found here.
This will put your foglights on a relay system and ease the load on the system. This method uses the existing wiring and switches to operate the foglights and headlights as the factory setup used to. I highly recommend this if you plan on keeping and driving your 35th very often at night.

I hope this information is helpful to you and improves your enjoyment of your vehicle while improving the safety and visibility of night driving.

Disclaimer: This article is for personal use only and for assisting owners in maintaining their vehicle. No publishing or reprinting is allowed unless by permission by the author of this article. The author is not responsible for any damage that occurs from the use of this information.