headlight switch
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Joined: Jan 2001
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From: Virginia
The connector is notorious for overheating. You can buy a plug with a pigtail to repair it. Also check the tan/white wire. It's what feeds the power to the switch for the running lights, and is known to melt and burn out. There is a separate power feed to the switch for the headlights.
And as the connector overheats, it also ruins the switch.
And as the connector overheats, it also ruins the switch.
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Senior User
Joined: Jun 2010
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From: Goose Bay, Labrador,CA
The ceramic disc in the switch itself gets warm even with just the parking lights on. Makes we start wondering if there's a short somewhere. I can see if the headlights were on, but with just the parking lights? Hmmm.
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Joined: Sep 2010
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I had problems with my head lights going out at night. Tried replacing the dimmer switch and other things. Replaced the headlight switch and haven't had the problem again. I did notice that the old switch was warm to the touch. This was on a 1884 F150.
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Joined: Jul 2007
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From: Humble, Texas
I had the same problem on my '85. Replaced the switch and all was good for awhile then it started doing it again. Usually, when I would hit a bump. Since the switch was new, I looked at the harness. I turned the lights on (someone to help to watch the lights when you do this during the day would help) then I put my finger on each connector in the plug and wiggled each one (from the top of the connector plug) til I found the one that was causing the problem. Turned out the connector on the end of the wire was loose. I pulled this one wire out of the plug, cut off the connector and crimped a new one on. Pushed it back in the plug, plugged it back in and have not had any problems since. Beware, there is not a lot of slack in that harness. You have to do all of this lying on your back on the floorboard. You'll need a flashlight if your eyes are weak like mine, a sweat rag when the sweat gets in your eyes, someone to write down the new cuss words you'll be inventing in a fluid stream and last but not least a good chiropractor to straighten out your spine when you're done. But, Hey, at least my lights work now. Hope this helps
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Senior User
Joined: Jun 2010
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From: Goose Bay, Labrador,CA
Seems like many of you have had issues with your headlights going on and off. My headlights have not been affected. I did try wiggling all the wires going into that connector with no success. My harness connector isn't quite as tight as you speak of. I have it hanging out the front of the dash. By the way, does anyone know how that switch is grounded? Like I said earlier, on the old Ford parts truck of mine which is also a 1980, the switch had a ground connector actually coming out of the back.
Post Fiend
Joined: Jul 2004
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From: Northern California
Was talking to a friend who knows a bit more about these things. He says there must be a short somewhere around that switch connector. Also says to put grease in there. What sort of grease are we talking about? I can get a tiny tube of the stuff but is there other grease that will do? By the way, I wiggled the wires around this morning with no success. Lights not working. As well as horn. The horn must be connected to this circuit.
If you have power at the Black/Orange wire, but not at the Yellow/Light Blue Dot wire, then replace the headlamp switch.
If no power at the Black/Orange wire, then you have a fault in the wiring between the switch and the Starter Solenoid. The headlamps get it's power from the starter solenoid/battery connection.
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Post Fiend
Joined: Jul 2004
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From: Northern California
Be aware that the connector for the 1981-1986 switch will fit on the 1980 and visa/versa, but the wiring in the connector, and the switches themselves are internally different, and they are not swappable. Trying to put a 1981-1986 switch in your 1980 will cause the issues you are describing. Also a defective switch will cause this.
Follow the tests in my previous post, and that should get you started in the right direction.
Posting Guru
Joined: Aug 2009
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From: Mexia, TX
I was at the junkyard yesterday and it appeared to me in one truck that the headlight switch and wiper switch mount to the same metal bracket behind the dash. I suppose that's how they ground. What's strange is, I pulled an intermittent wiper switch set (switch and governor) and the switch has a separate ground wire coming out of it, whereas my original two-speed, non-intermittent switch didn't.
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From: Virginia
I took a quick glance at the diagrams, and I don't see a ground shown for the headlamp switch, and I can't think of any reason off hand why the headlight switch would need a ground. I know you have one, but I can't think what it would be for and if it's really all that important. Maybe someone else knows.
Post Fiend
Joined: Nov 2005
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From: Charles Town, W bygod Va
The ceramic disc is the rheostat for the dash light dimmer, it is going to get hot. There is a thread in the stickies on how to add relays to the headlight circuit that will make your headlights a little brighter and reduce the current that goes through the headlight and dimmer switches, eliminating the meltdown problem. I bought relays about a year ago to do it but havent yet.
Post Fiend
Joined: Jul 2004
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From: Northern California
On the back side of the disc there is a spring. When the ceramic disc heats up too much, the spring expands and trips the breaker.
This is NOT the same spring as the rheostat on the front side that goes around the circumfrence of the disc.
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Senior User
Joined: Jun 2010
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From: Goose Bay, Labrador,CA
Thanks for all the great feedback.
Got my headlight switch today and hooked it up. The lights come on consistently. I'll keep an eye on it. I think I'll use it a bit before putting the dash panel back in place. It's a pain trying to get that wiper switch button off.
Got my headlight switch today and hooked it up. The lights come on consistently. I'll keep an eye on it. I think I'll use it a bit before putting the dash panel back in place. It's a pain trying to get that wiper switch button off.
Post Fiend
Joined: Nov 2005
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From: Charles Town, W bygod Va
I finally hooked my headlight relays up.. guess this thread inspired me. It took a while because I also rewired my plow lights and used relays for them and had to figure out my own wiring diagram. I might change it a little so I can burn truck and plow lights at the same time, I also thought about wiring it up so the headlights turn off with the ignition switch.... maybe next year.