No Low-Beams '94 f150

Drove to a restaurant with low-beams. Ate dinner. Started truck to go home. Now low-beams. High-beams work great (to the annoyance of everyone in front of me...), parking lights work great. I highly doubt both low lights would go out at the same time. I checked all the fuses - interior and exterior (even though only a few might apply).

Any ideas? Besides the stupid switch. Why does every vehicle I drive require a new headlight switch.. RRRR (you don't have to answer that..)

Thanks for any help offered.

Mike W.

Reply to
MW
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Okay, I'm looking at the wiring diagrams on

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(Mitchell site - great site). It shows the main switch flowing to the multi-funciton switch, then to the headlights. The multi-function switch was replaced because my wipers weren't working. So I would assume this isn't it. Maybe I shouldn't assume that.

But when I flip the main switch from parking lights with no headlamps to WITH headlamps, the parking lights flick off in between locations on the main switch, indicating to me that it recognizes the switch to headlights.

MW

Reply to
MW

A clue! Maybe when the multi-function switch was replaced, one of the wires didn't terminate tightly? Came loose when you weren't lookin'. More likely than a faulty new switch, but with parts these days....I wonder what was wrong with the old-time high/low headlight floor switch? Prolly too reliable....

Dave S(Texas)

Reply to
putt

spoken like a Texan (smile). They have a problem of shorting out in northern climates, something to do with snow and salt being tracked into vehicle in winter months. Also corrosion issues for the same reason. Dodge had some serious problems with fires because of that in the mid 70's to early 80's to the point that while in the service we were issued a "modification work order" to ether remove all the insulation from the floor mats, or remove the floor mats completly for all M880 and M890 series 5/4 ton Dodge trucks.. All they did is move the darn thing up on the steering column and run a rod down to it from the stalk. I replace a lot less highbeam switches since the move was made. Another easy money repair lost.

Whitelightning

Reply to
Whitelightning

I just cannot believe it..... Both bulbs burnt out at the same time. Went to the local parts store, bought new lamps, threw 'em in... bingo. I am relieved, but bewildered. Maybe God graciously did this so I could replace both at once instead of making two trips, I dunno. =)

Thanks for your idea bout the switch, I had the same thoughts running through my head about whether they did it right or something.

MW

Reply to
MW

Maybe all that voltage that was able to pass thru a good MF switch was more than the old darlin's could handle!

Lugnut

Reply to
lugnut

I do believe you just learned O'Brians' Law.

Whitelightning

Reply to
Whitelightning

You said that you had the low beams on when you shut the truck down. OK, you probably turned them off before you shut off the ignition but for both to burn out at the same time indicates a power spike thru the bulbs. It may have been a "one-time" event or it may be a symptom of other problems. If the same thing happens again in the not too distant future, I would suspect the switch that was recently replaced.

Dave D

Reply to
Dave and Trudy

I'm curious about this: where/how in a 12v system could this 'power spike' occur and why did it affect only the low-beam element in the headlamps and no other electrical component of the vehicle?

LOL...good one!

Dave S(Texas)

Reply to
putt

If they were the only components energized thru the suspect switch and the power spike was cause thereby, they would be the only component affected. Quite simple when you use a little thought ,

Reply to
Dave and Trudy

Dave/Trudy....your knowledge of electricity/systems is astounding. Your 'little thought' process is common to all DIY's....wtg

Dave S(Texas)

Reply to
putt

I had this problem many years ago on a '70 Plymouth. No low beams, but the high beams worked fine. Spent a whole weekend in the driveway with a meter tracing down the wiring, switches, etc., and could not find a wiring problem.

Finally discovered the problem. Both low beam lights were burnt out. Could never happen again in million years having both burn out at the same time, but it did.

RCE

Reply to
RCE

Heh. I should have read a few more posts.

Congrats! I thought I was the only one on earth that ever had that happen.

RCE

Reply to
RCE

Anything in the circuit that has some inductive reactance (coil, windings, etc.) could cause a spike when the field collapses.

RCE

Reply to
RCE

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