losing headlamp ever few weeks?

[tyroneweaver]

lamp still working.......so far so good

LED??? Would draw less amps. When I was driving truck seemed like all my electrical problems were grounding

 

[Alystyr]

Electrical problems can be a bear to diagnose, even for life-long mechanics.
Now, I'm just throwing a idea out, but it almost seems that the lamp may be getting a little too much juice (as in amps, not necessarily volts).
That would possibly cause the bulb to have a shorter lifespan, the same way that a fuse will blow faster if it's a lower rating than it should be.
The next time you have a chance to have it checked out, have the mechanic compare the amps/volts between the two sides' sockets. If they aren't close in values, then that could give your mechanic somewhere to start looking for the cause.

 

[Moonglow]

But remember, amps has to be tested with the test leads in series, crossing the wires for amps will short out the circuit....

 

[Pop23]

I think it's doubtfull its electrical. Changing the bulb would not make that big of a differance. It would burn out much faster then two weeks.

I like the thought that moisture is getting to it, or it's getting jiggled in a loose socket.

 

[leftwinger]

You turn on the headlamps with a switch, correct? One side is OK but the other is not? The "on" switch simply applies 12V to one side of the headlamp and the other side goes to GND. Maybe thru a fuse to keep from frying the wires if you connected the hot wire to ground (short out the headlamp).

Maybe switch is bad? Hard for a mechanical switch to blow up bulbs? An active switch maybe?
Maybe there is too high a fuse allowing too much current thru the lamp?

Need to know what kind of car........kind of bulb.....etc.

Put the old bulb in the problem side. And the new bulb into good side. See if problem is bulb or you or socket?

 

[Alystyr]

I think it's doubtfull its electrical. Changing the bulb would not make that big of a differance. It would burn out much faster then two weeks.

I like the thought that moisture is getting to it, or it's getting jiggled in a loose socket.

If the amps are only somewhat higher than spec, then the bulb's life is reduced. The higher the amps, the shorter the life.
If it's too high (i.e. dead short) they could possibly pop like a flashbulb.
However, it is true that vibration and moisture aren't friends of headlights.

 

[Alystyr]

The "on" switch simply applies 12V to one side of the headlamp and the other side goes to GND. Maybe thru a fuse to keep from frying the wires if you connected the hot wire to ground (short out the headlamp).

Yeah, things used to be that simple.
Today, the electrical system of a car has things so interconnected that one bad ground connection in the back of the vehicle can literally shut everything down.

 

[leftwinger]

As poster(s) say Vibration in socket would not be good. Vibration would be like turning it off/on fast. Switch could also do that. Especially if switch it active......not mechanical like olden days. Active is like a Transistor comes on and the current starts to flow from 12V thru fuse thru lamp thru SWITCH DEVICE to GND. Switch device is either a Relay, Mechanical or Active. Could be bad relay?

Fuses? I don't know if they have separate fuse to each side headlamp? doubt it. cost. Probably a 10A - 25A circuit? pretty high AMPS to get a lot of light out of two lamps running "on"at 12V thru the bulb filament.

Is one side brighter than other? Does it go on/off sitting there? Does it flicker while bumps? I know hard to tell.

You buying the correct bulb? That is why I said switch sides.....just a thought.

 

[leftwinger]

The more I think about it: well. The Bulb itself determines the AMPS that flow. The resistance of the filament is the limiting factor. Provided both sides wiring path is same, then I don't see how you could get too much current thru the path to the bulb to blow the bulb.

Unless they have some magic limiting built in resistance/resistor to each bulb and one side is missing?
If it looks normal for a while...........then as the poster said. Vibration while driving maybe?

I am completely out of control! self imposed ban from posting.

 

[leftwinger]

Yeah I am back. sigh.

If you can find any relay (probably near the fuse box) labeled Headlamps, pull it out and look at contacts. Tap it a bit if looks ok and put re-seat it into its socket.

Could be....could be. You may have to replace it if it is bad.

Ideally........maybe there is a relay you don't use........similar and you can move it over!!

win-win. Now I am out. O...U....T!

 

[leftwinger]

One more. When you turn on lights, you use a switch. They usually don't switch 25A thru a switch anymore. They turn on a big relay under the hood.........and the big current flows thru relay contacts.

Little current flow thru switch primary side of relay. At least that is what I suspect it is. This relay may have two side of it. One side for each headlight. Maybe side 1 is chattering?

just a thought. I never stop rambling ............ evidently.

 

[Pop23]

One more. When you turn on lights, you use a switch. They usually don't switch 25A thru a switch anymore. They turn on a big relay under the hood.........and the big current flows thru relay contacts.

Little current flow thru switch primary side of relay. At least that is what I suspect it is. This relay may have two side of it. One side for each headlight. Maybe side 1 is chattering?

just a thought. I never stop rambling ............ evidently.

Moisture should be easy to see. To get enough to blow the bulb anyway.

Here's an off the wall idea. Anyone who's gone to the same auto shop and gotten 3 bad alternators in a row can attest. Buy the new bulb from a different shop, you may simply be getting the bulbs from the same bad batch.

It's an idea anyway

 

[NYcarbineer]

subbie...2005 .....the drivers headlamp keeps burning out after a few weeks....i dont even know where to start looking for the problem...

Try an H7 LL bulb, if you're not already. LL stands for long life.
Philips 12972LL 55W H7 Long Life / Subaru 84920-AG020

 

[BruSan]

Another suggestion for you is to try some dialectic grease on the contacts and grounding prongs as well as the fuse legs.

My personal favourite was marketed by Grote the same people who supply a lot of heavy duty truck LED lighting. I normally just poke a "Q" tip into the tube nozzle then wipe the contacts and bulb base liberally with the stuff and it will guarantee a non-oxidizing contact, seal out moisture, and even dampen some vibration.

Multi-plexed computer controlled truck circuitry can give you migraines trying to chase down gremlins and that tube of Grote will eradicate 90% of your problems if you remove ground contacts, clean them good, coat with dialectic grease and reassemble them. Use the stuff on battery connections and say good bye to the white/green oxidation efflorescence build-up forever.

High amperage headlight bulbs are the worst offenders due to the hot cold cycle drawing any humidity laden air into the socket when the cooling down occurs when shut off after a period of being on.