Hello to everyone out there. I have an unusual problem with the headlight switch on my truck. I replaced the switch and now the switch makes a ticking sound and the parking lights in front blink on and off as if they were emergency flashers. The headlights come on but the tail lights do not. the turn signals work normally and the dome light comes on normally. This is a 59 custom cab. Does anybody know what is causing this?

 

I'm not sure what could be wrong but maybe this information will help. The ticking and blinking is caused by the internal circuit breaker in the headlight switch. It's purpose is to keep your headlights from total failure. I guess the designers figured that blinking headlights were better than none in the event of a short. The parking lights are not normally connected to the circuit breaker but fused instead so I would not expect them to be blinking. Were the lights working normally before you changed the switch? Since there is essentially only one plug that attaches to the switch, if everything was working beforehand, it's possible you have the wrong switch. If things were not working okay before you changed the switch, it sounds as if you have a problem elsewhere in the parking light and/or tail light circuit. Tell us why you changed the switch and perhaps that will yield another clue.

Lou Manglass

 

Chances are the new switch in and out positions are different than the old one and you are feeding it in power where the taillights should be coming out. It's clicking as previously mentioned because you have the power wires doubling up the voltage on that one setting.

Are you using a stock switch or something generic from NAPA, etc. Let me know and we'll get it figured out. Meanwhile, there's a wiring diagram for headlight switches in my #2 gallery if you want to check that out.

J!

 

Thank you both for your interest in my problem. To answer some of your questions; yes the lights were working normally until one night when I noticed that the headlights would dim for a fraction of a second, sort of like a blink. This dimming would happen about every ten seconds, or so. This continued for a few nights and then one night the lights just went out as I was driving down the freeway. I cycled the switch a few times in the dark and got the lights to come back on but they would not stay on for long. Of course I passed a cop just as the lights were blinking off and I got pulled over. I told him that I couldn't understand why a 50 year old truck would act this way. He laughed and let me drive the few blocks home without a ticket. I figured the switch was bad so I replaced it with an NOS ford switch (110.00) ouch. As soon as I tried the new switch I noticed the thumping sound. After reading your posts,I thought about how the thermal switches inside the unit might be telling me that I have a short somewhere. The headlight switch has separate posts on the back for the front and rear running lights. I pulled the rear wire off of the post and The headlights and front running lights are working perfectly. I ran a fused wire from the battery to the rear running light wire and the fuse burned out. So now I believe I have a short in the rear wire. I will check this out today and let you know what happened. I now surmise that I had a short from the beginning of this story and the short was causing the thermal switches to separate and thus cause the intermittent headlight blinking. The voltage would change every time the thermal switches opened and closed. I may have replaced the headlight switch prematurely, but it's OK because now I have a brand new one. Thanks again for the help and I'll keep you posted.

 

Let us know how it works. You realize that power goes into yout headlight switch in two different places. So there are actually two separte circuits flowing through the switch. Good headwork on the troubleshooting!

I'll post my diagram if for no other reason than to bump this back the top.



Good luck,
Julie

PS 59 switch may be a little different - check out the letters of the terminals.