Help! My LF Headlamp Won’t Turn On

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George House
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Help! My LF Headlamp Won’t Turn On

Post by George House » Tue Sep 29, 2020 12:46 pm

...and I have an 11 pm Saturday night wedding getaway car event ! At first they both didn’t work but by meticulous electrical tracing with a trouble light and parts replacement (headlamp socket and thimble) the RF lit up. I cleaned the contact surface in the headlamp shell with a dremel tool and brush. And I have good electrical ‘fire’ behind the switch at both dim and bright. Also at the terminal block, headlamp socket and thimble. Also have many bulbs that all test good on an original bulb, coil and spark plug tester. Taillamp works great. What’s my problem ??
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One of the biggest problems with today’s youth is they’ve never known the fear of hearing leather being rapidly pulled through seven Wrangler belt loops.


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Re: Help! My LF Headlamp Won’t Turn On

Post by Andy Loso » Tue Sep 29, 2020 12:59 pm

Good ground thru the stem of the headlight bucket to the frame?

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Re: Help! My LF Headlamp Won’t Turn On

Post by Quickm007 » Tue Sep 29, 2020 1:09 pm

May check your ground...
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Re: Help! My LF Headlamp Won’t Turn On

Post by paulmikeska » Tue Sep 29, 2020 1:15 pm

Check that the thimble the bulb mounts in for a good ground. I usually solder a wire to the thimble and connect to a direct ground.


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Re: Help! My LF Headlamp Won’t Turn On

Post by Norman Kling » Tue Sep 29, 2020 1:17 pm

check your ground. Check the bulb, Push in on the bulb. If it lights, there is poor contact between the socket and bulb. Some times a little solder on the contacts at the back of the bulb will build up the connection and make it work. If all else fails and the dim light works, temporarily switch the wires and use the dim side. It's not as though the lights give you much vision anyway, just want to be sure they are both lit so you won't be cited for no lights.
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Re: Help! My LF Headlamp Won’t Turn On

Post by RustyFords » Tue Sep 29, 2020 1:33 pm

Check continuity between the headlight bucket and somewhere else on the car where there should be a good ground....like the frame, etc.

No continuity, no ground....no workie.
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Re: Help! My LF Headlamp Won’t Turn On

Post by Susanne » Tue Sep 29, 2020 2:18 pm

Bad ground or a broken wire. It's not a mag headlight, but the cause would be the same. On a series mag-powered headlight circuit (like on the 15) that indicates the crossover feed wire is grounding out before it reaches the Left headlight...

All of the above. Wring, rinse, repeat!

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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Tue Sep 29, 2020 2:27 pm

Thanks guys... no luck yet ... still working. Dumb question: the receptor the brass adjuster screw attaches to divides the socket roughly 45/55. Does the shorter end go to the rear- unlike this picture? Once more, there’s electricity to the thimble and socket. Have many bulbs and they all test good.😞
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Re: Help! My LF Headlamp Won’t Turn On

Post by paulmikeska » Tue Sep 29, 2020 2:59 pm

Can you feel/see the bulb depressing the contactsin the thimble when you turn the bulb? As stated by Norman above I have had to build up the solder contacts to get a good electrical connection. With the power on and the thimble exposed attach a test wire to the neg side of the battery and touch the other end of the test wire directly to the thimble. With the test wire connected switch from high to low. You could still have a broken wire. You are missing either the positive or negative, or both, if a know good bulb will not light up.

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Re: Help! My LF Headlamp Won’t Turn On

Post by George Mills » Tue Sep 29, 2020 3:16 pm

Hook up the wires and thimble to that socket you show, insert a bulb in the other end, turn the lights on, press that shiney part against bare metal on the horn bracket or such.

Sounds like it is probably going to light...

if so...grounding as others have mentioned. Headlights are notorious for weak grounds! The path... You have the socket housing which must be clean, you have the focusing screw as the socket needs to slip fit, you have the reflector to the lamp housing that may or may not help, you have the focus screw to 'bucket', you have the bucket to the front axle (unless it has the light bar) and then it should be good from their back providing your ground strap is tight?

Might want to check the right front along the same lines. It lights now because you wiggled it and cursed at it! Karma exists...

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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Tue Sep 29, 2020 5:46 pm

Great suggestions All ! Thanks ! But this is what I’m dealing with. I have ‘fire’ all the way through the mounted thimble and socket. So it’s not a bad ground situation,..right? And the bulb is shining (see pic of original bulb, spark plug and coil tester) I’m still at a loss ... Magic ?
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Re: Help! My LF Headlamp Won’t Turn On

Post by CudaMan » Tue Sep 29, 2020 5:50 pm

Does that test lamp have its own separate ground? If so, you just proved that you have strong voltage on the positive side of the bulb, but a poor or no ground. If time is short and you just need to "get her done" temporarily, run a separate ground wire from the shell of the socket to a clean, bare spot on the frame (like where you grounded your test lamp).

Just remember, "There is nothing more permanent than a temporary fix that works!" Good luck. :)
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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Tue Sep 29, 2020 5:52 pm

Headlamp bulb shining brightly
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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Tue Sep 29, 2020 5:59 pm

Thanks Mark. I think that was Paul Mikeska’s suggestion too. I’ll try it. Want to get’er done before The Debate tonight
One of the biggest problems with today’s youth is they’ve never known the fear of hearing leather being rapidly pulled through seven Wrangler belt loops.


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Re: Help! My LF Headlamp Won’t Turn On

Post by bobt » Wed Sep 30, 2020 6:08 am

BAD GROUND BAD GROUND BAD GROUND!! RUN A TEMPORARY GROUND WIRE FROM THE BATTERY NEGATIVE TO THE BULB SOCKET TO TROUBLESHOOT.

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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Wed Sep 30, 2020 10:36 am

Great frustration ! Wire from battery negative to headlamp thimble doesn’t light bulb. Ground wire from headlamp adjusting screw to frame also doesn’t light bulb. However, without those 2 attempts, I did get a barely discernible glimmer this morning - see pics.
.... Oh how I wish the bride would’ve selected the ‘19 centerdoor 😞
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Re: Help! My LF Headlamp Won’t Turn On

Post by George Mills » Wed Sep 30, 2020 11:23 am

Other George,

Known 6 V to thimble contacts -checked with volt meter Yes? Check...

Socket housing to ground jumpered for good contact Yes? Check

Bulb is a 6V lamp as it does light on test box Yes? Check

Hate to say it buddy, short of the bottom contacts on the lamp barely kissing the contacts in the socket, the lamp HAS to light!

Other than that, the dim you see is either the real dim and that’s just the way it is...or...something is going to get mighty warm mighty quick. Just for kicks, exchange the two wires at the thimble and try again? (If that doesn’t get you a eureka moment, change them right back before you forget


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Re: Help! My LF Headlamp Won’t Turn On

Post by Dan Hatch » Wed Sep 30, 2020 11:27 am

All of my cars I drive I install a ground wire from the socket the bulbs go in ( NOT the socket in the bucket) to a ground on the bucket. I clean a spot inside the bucket and use a big iron to so
Solder it. Then make sure the bucket has a good ground. Works every time. Dan


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Re: Help! My LF Headlamp Won’t Turn On

Post by John kuehn » Wed Sep 30, 2020 11:50 am

When the head light buckets go repainted did you make sure the bucket socket doesn’t have paint in it? If it’s painted there’s not a good ground.

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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Wed Sep 30, 2020 12:14 pm

I’m getting closer guys. Thanks for hanging in there with me. After speaking with my buddy Paul in the mile high city, we agreed that I remove the LF headlamp and inspect under the base where it mounts to the accy headlamp bar. Sure enough, shiny black like the buckets.High speed wire brush removed the paint and reinstalled. Still just the above glimmer. So I reinstalled the long wire from battery neg. to headlamp and - viola - bright LF bulb !! Where do you think the bad ground is in this bucket ? I first dremel wire brushed the sheet metal cylinder integral with the bucket and am using a new socket and known good bulb. I don’t solder. There is a pad under the headlamp bar but I tightened the 2 carriage bolts real tight
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Re: Help! My LF Headlamp Won’t Turn On

Post by TRDxB2 » Wed Sep 30, 2020 12:33 pm

Been thinking if using some Bulb Grease around the headlight base that wedges into the fender bracket would help. What confuses me is that its refereed to as dielectric grease which is non conductive. But instructions say to wipe around the threads of a bulb to prevent corrosion - doesn't make sense since that would insulate the bulb from one connection.


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Re: Help! My LF Headlamp Won’t Turn On

Post by jab35 » Wed Sep 30, 2020 1:15 pm

There's sufficient metal to metal contact through the grease to light the lamp. The grease helps reduce oxidation of the bare metal adjacent to the contact points so the bare metal to metal connection is preserved, and so you can get the thing apart after its been exposed to the elements for some time. jb


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Re: Help! My LF Headlamp Won’t Turn On

Post by Norman Kling » Wed Sep 30, 2020 1:49 pm

Since the right light works, it is certain that the frame is grounded to the battery. The points to check would be the inside of the socket in the headlight where the socket for the bulb slides in. The place where the light attaches to the fender. The fender support arm at the end where the light is attached and the end where it fastens to the frame. Any of these points could be painted or rusty. If you don't want to take everything apart, take a wire from the frame where the light is fastened and touch the other end to the socket. If it lights, your bad connection is between those points. Then move the wire to the bracket at the end where it is attached to the fender. The bad connection would be between the points where the light burns and the point where it does not burn. You are on the right track.
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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Wed Sep 30, 2020 2:28 pm

Another phone call with Paul Mikeska. He suggested adding the reflector. It might aid the socket/bucket grounding. This I’ll do after some honey-do s.
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Re: Help! My LF Headlamp Won’t Turn On

Post by RustyFords » Wed Sep 30, 2020 2:36 pm

If you don't have a multimeter, go get a cheap one at Home Depot/Lowe's/etc.

Set it for continuity. That basically tells you if electric current can run between where one of the leads is touching and where the other lead is touching. Most of the multimeters will give you a little electric musical note to tell you there's continuity. You can test it by touching the two leads together.

Now go to your headlight and find out if there's continuity between the actual socket body (ground) and the headlight bucket. If there is, then keep testing further and further away from the socket. You should end up with continuity between the socket and somewhere far away....like the frame. You may need to scratch the paint a bit to get to bare metal, so if your car is a pretty one, do that where the scratch can't be seen.

This method will tell you where your ground is failing.
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Re: Help! My LF Headlamp Won’t Turn On

Post by kmatt2 » Wed Sep 30, 2020 2:58 pm

If you are still having problems getting a good ground at the head light bucket you can try using star washers under the nuts at the fender iron mountings to the bucket and frame horn. The star washers have upsets that help make better contact thain just the nuts, there for a better grounding connection.

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Re: Help! My LF Headlamp Won’t Turn On

Post by George House » Wed Sep 30, 2020 4:21 pm

The Beatles sang it best 🎼“With a Little Help From My Friends” 🎵 Thanks to all !! Every contribution pushed me a little farther toward success. See the multimeter in the foreground 😁
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Re: Help! My LF Headlamp Won’t Turn On

Post by Quickm007 » Wed Sep 30, 2020 5:14 pm

Congrats George ! Well done!
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Re: Help! My LF Headlamp Won’t Turn On

Post by Novice » Wed Sep 30, 2020 5:35 pm

Congratulations. now if You replace your old bulbs with 6 volt leds You get twice the light at a fraction of the current. I can just barley see the amp meter needle move on bright. Good luck with the weeding party.
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Re: Help! My LF Headlamp Won’t Turn On

Post by DHort » Thu Oct 01, 2020 5:00 pm

Great job George. Knew you could do it. You get an extra glass of champagne.

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Re: Help! My LF Headlamp Won’t Turn On

Post by RustyFords » Fri Oct 02, 2020 11:39 am

Congrats George!

I'm no electrical wizard by any stretch of the imagination, but a multimeter is a super handy thing to have around. I watched a few youtube videos on how to fully take advantage of the basic functions of a multimeter and learned quite a bit.
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