As I'm driving, or even just idling with my lights on, I notice one of my headlights will go out, and then come back on a few minutes later. Both of the lights have done it. They'll go out, and then come back on a little later. Usually it's one at a time, but last night I was driving and I had my high beams on, because then both lights will typically be on. As I was driving, I noticed my "HIGH BEAM" display light on the dash went out. I hit my high beam foot switch a couple times, and I couldn't get them to come back on. Then, I realized neither of my headlights were on. I stopped, turned the truck off, waited, turned it back on, and then both lights worked fine. How do I fix this?
Yes, it wouldn't hurt to replace the Headlamp switch. The circut breaker in the switch deteriorates with age. Very comon problem.
However, the circut breaker will make BOTH lights go out simutaniously, not one at a time, like you mentioned, so there may be another problem under the hood, triggering the circut breaker. Check the wiring going to the headlamps, under the hood for cuts, abbrations, shorts, etc.... It could also be a faulty headlamp itself.
It's also good practice to replace the dimmer switch at the same time as the headlamp switch.
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I do believe you have a problem triggering the headlamp circut breaker, rather than the breaker itself being at fault on this occation.
Replace the switch; I'd hit the junk yard and pick up a few. The other thing to look at is the alternator's output voltage. Make sure it's 14.7V +- under load. Ohms law states that E=IR, which means that as the voltage (E) drops (low alternator voltage output at idle), the current (I, amps) thru the headlight switch will have to increase to maintain the wattage output at the load (R, headlamps) which could cause a weak headlight switch breaker to open.
A strong battery and alternator will provide consistant bright lights and lower current flow thru the entire vehicle electrical system. Increasing the idle speed a couple hundred RPM on my '85 was all it took to remedy the dim lights and slow wipers at idle. Good luck
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as the voltage (E) drops (low alternator voltage output at idle), the current (I, amps) thru the headlight switch will have to increase to maintain the wattage output at the load (R, headlamps) which could cause a weak headlight switch breaker to open.
I disagree with the above. If the headlights increased the current through the switch when the voltage dropped, that means they would not dim(the wattage use would be the same). But they do dim, which means there is less wattage being used, which means less voltage or current is being used, or both are less(which is true in this case).
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A strong battery and alternator will provide consistant bright lights and lower current flow thru the entire vehicle electrical system.
The next statement is true for some loads, but not the lights. As the voltage is increased, they get brighter, and more current is flowing and the wattage output of the light is increased. It's a well known fact that if you put a relay kit in your harness to decrease the voltage drop, and make more power available to the lights to make them brighter, the life of the headlights will be reduced because they are burning more aggressively, shortening the life of the filaments. Of course this is usually an accepted trade-off to get better lighting on the road.
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i would also change the switch, ive put 3 in my 82 since it was new
Next time you may want to check the plug in the harness that the headlight switch plugs into. The connectors get loose, which causes the plug to melt and cause an even worse connection problem. The heat from the poor connection will also cause the circuit breaker in the switch to trip. I believe Ford used to sell a plug with pigtails for this problem.
As I'm driving, or even just idling with my lights on, I notice one of my headlights will go out, and then come back on a few minutes later. Both of the lights have done it. They'll go out, and then come back on a little later. Usually it's one at a time, but last night I was driving and I had my high beams on, because then both lights will typically be on. As I was driving, I noticed my "HIGH BEAM" display light on the dash went out. I hit my high beam foot switch a couple times, and I couldn't get them to come back on. Then, I realized neither of my headlights were on. I stopped, turned the truck off, waited, turned it back on, and then both lights worked fine. How do I fix this?
If it's when you hit the high beams, may be the high beam switch. I have the floor "kick" switch. Sometimes they would go out when I kicked them on...I replaced it for $3 and some change...took about 10 min. to change it out...no probs since.
There is most likely some bad wiring somewhere. I glanced at it the other day and I noticed one of the wires going to the headlight bulb on the right side (the one I've been having the most trouble with) has no insulator on it. Sketchy... Someone must have messed with it. I'm going to look into it more... Thanks for the help.
Had the same situation in my 83 . Replaced the dimmer, Thought it was fine. Small time past , then problem started again. Couldn't recreate it at home with any certainty, so I replaced the switch with an aftermarket one. All better for about a month.Yikes ! (I have seen the head light wires you speak of , I think the wire shielding shrinks and exposes the copper after the years and besides that may get pulled back wires abit when pulling the connectors for bulb replacement.) So I open up the old switch (Ford) and the Now removed New switch and found the new switch had a very inferior build compared to Ford(motorcraft) part and that the new switch(made in chy) had been broken upon assembly(small piece floating around inside not related to my careful disassembly ). The Ford piece is of greater value. Thicker contacts and all. I went to dealer and bought motorcraft and Its working 3-4 yrs later. I've got the factory wiring diag. and if I recall the Two head lights are fed through separate leads into switch? But at any rate the switches do see alot of heat and can burn contacts. My 2 cent. Best wishes
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Have had the same problem.Replaced the dimmer switch,and that cured the problem.
