Weird headlight issue.... ideas?

Here's my issue:

I was driving along and noticed my passenger headlight wasn't on. If I turned my brights on, they worked fine. But when I switched back to regular lights, the passenger light was off. After a few minutes it would come back on (and no, it didn't occur after I hit any kind of bump). The headlights would both stay on then until I hit the brights again, then when I switched back from brights to regular, the same thing would occur. After a few minutes the headlight would come back on. Well, after a week or so that passenger headlight failed totally (that is except for the brights, which still worked fine) I replaced that headlight.
For a couple of weeks it worked fine, then the NEW headlight stopped working also! (it didn't do the whole "off for a few minutes, then back on" thing) Oh, and the brights still work.
So now I'm wondering... do I go get ANOTHER headlight? I'm gonna look around for a short somewhere but it's not really acting like a short... It's been out for a few weeks now. Ideas? Do I have a gremlin? (the monster, not the car)

I would check to make sure the connector is not bent or green,
bad contact has been a problem for me in the past

sounds like you have short before the light wires. Maybe a coating on a wire. Try tracing the wire as far as you can....all i can say.

I guess I should add that the "bad bulb" doesn't work on the driver side either. So the bulb really is dead... the question is whether a short or overload is killing it...

Someone was telling me that Jeeps have a condenser for the headlights... is this just for OLD jeeps?

My Father had the same problem with his Pathfinder. replaced the bulb but kept happening. So he started looking for an open rather than a short. Turned out to be the switch not making contact, he cleaned up corrosion on the switch and it fixed it for a little while then he sprayed it with WD-40 and it's worked ever since. I hope that gives you some ideas.....

oh and it was the High beam/ low beam switch, just to clarify
HTH

xj blue... how does that explain the bulb not working in other locations now? The bulb IS bad at this point. Do you think a failing switch would cause that? (honest question)

This can't be caused by a short or bad switch if the lamp is burnt out. Over voltage is a remote possibility but that would tend to burn out other lamps as well. You can check the voltage to be sure. Should be around 14 volts with the engine running. I had a similar problem with the brake light on my van. Same light burnt out twice in a row and the third lamp has been fine for 5+ years. Might as well try another headlamp.

In the defence of xjblue......(but not at the switch--somewhere in the harness to that particular lamp)

It could be a faulty connection to the bulb. If the bulb is being switched on, and off really fast (by the faulty connection), you may not even notice it visually, but it will impact the life of the bulb.

Put a good bulb and start shakin', and yankin' on your connections, and see if you can get the bulb to go off.

Also, you may want to connect a meter to the lamp connector and see if you get voltage fluctuations.

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Ok. I can't find the supporting evidence for what I just said but I know I read this in some tech info published by a manufacturer of halogen lighting, and incandescent bulbs.

A couple of things;

1) The life of a Halogen bulb is greatly reduced by operation at a low voltage. That is because the glass does not get hot enough to redeposit enough of the filament molecules back onto the filament. Filament gets thinner faster -- bulb dies faster.
(this fails to explain why my headlights running with DRL module at 5Volts are still good after 2 years, but I believe the theory is still correct).

2) Filament bulbs do not like being switched on, and off very much. Electrical, and thermal surges will reduce the life of the bulb. (ever notice that a standard house light seems to burns-out/pop right as you turn it on)

Now since the Bulb is going bad I honestly don't know but I would second Lou in that checking voltages would be a good starting point. Find out whats going on voltage wise and then track down where it's coming from.

BTW I misread your second post (one of my contact lenses was out) so I didn't get it that the bulb was bad / sorry

Hope you can find the problem! I'm interested to see what you come up with in case it happens to me....

xj(I need to get my own multimeter someday)blue

Check the 6 pin connector just in front of the airbox,drivers side. This is where all the front lights connect to the main harness. These corrode and short out at this point, check it and make sure you have no green wires or broken wires. This could by the problem

" Filament bulbs do not like being switched on, and off very much. Electrical, and thermal surges will reduce the life of the bulb. (ever notice that a standard house light seems to burns-out/pop right as you turn it on) [/B][/QUOTE]

I'm not sure you can base the life of a DC bulb on what happens with AC. DC bulbs used as flashers generally last longer than if run continuously, and that is in fact one of the secrets to those little "bulb-saver" buttons you can buy to put into a household lamp - they are just a 1/2 wave rectifier that turns the current into pulsating DC.

I remember some years ago seeing a project in some electronics magazine to build a cheapo strobe light, based on the principle that a conventional bulb will last a very long time even if flashed at considerable over-voltage, as long as the "on" cycles are short. And emergency vehicles seem to manage all right with flashing headlights.

Of course I could be full of it...but if the bulb truly doesn't work in another position I'd bet it's just defective.

While checking wiring, though, don't forget that there is a plug right where the headlight harness passes through the bulkhead right behind the left headlight. The plug is hard to see, and might even need to be fished out. It is a favorite spot for corrosion, and worth keeping an eye on.

Just to add my thoughts on the "household light bulb" theory... 2 things...
1) I believe when the switch is first thrown in a house, you can get a small 'bump' in power.... weak filament = pop!

2) A cold filament suddenly being lit up is more likely to go out than a warm one. I.e. you probably don't see bulbs blow as often when being turned off and right back on.

I may be blowing smoke too though.

On the jeep front, I put my new bulb in and will watch it. (I don't have a multimeter) I'm also gonna check the connections.

SPOBI alert. I was able to check my statements more throughly. I was wrong about the running at lower voltage stuff. In summary, it seems any filament lamp run at a lower voltage lasts longer--despite many other factors.

BoiseXJ; You are absolutely right about the temperature of the filament. A cold filament draws as much as 10 times more current then a warm/hot filament.
This causes serious stress to the filament at start-up.

Matthew; The half-wave thing works because in essense the bulb is being run at a lower voltage(power averaging). Despite the switching, the filament is kept hot.

A bulb will run on AC or DC, but will live longer when run on true AC(not pulsing DC).(more filament recombination stuff/DC notching effect). Again. running at the lower voltage wins over other factors.

There are just way tooo many factors that affect the life of a bulb.

I'll stop talkin' now.