Headlights intermittent not working

[treeman]

I have a 2003 pre-facelift 3.0d. The headlights started working intermittently, one would not work, then would, then the other side might work, then not, then both not, then one does. Now neither work without flicking the switch 20+ times, sometimes I can’t get them to come on at all. All this happens on switching the lights on, but once on they always stay on.
Having searched through the forum, it sounds like a LCM issue. It’s wet and cold here in the uk at present and I wouldn’t be surprised if some moisture has got in.
I have 2 questions, firstly does my logic sound correct? I am miles from anywhere here so hard to get to garage in daylight and I’ve no diagnostic equipment. I am contemplating buying a used LCM off eBay and just seeing if I can get away without recoding it (don’t care if tamper light comes on)
2nd question, how feasible is it to install a simply temporary wiring switch and relay just to get the low beam lights working? The car is just a workhorse now, I’ve had it 19 and really don’t care about looks or odd setup, I just want the lights to work reliably so I can drive it until I find the cause of the problem.

[EODguy]

Sometimes it will help trick the LCM by having the lights in the off position and NOT turning them on auto until the LCM has finished its startup checks. If this works instead of starting in auto or immediately switching to on upon startup then the LCM is dying.

Sent from my SM-A730F using Tapatalk

[andrewwynn]

I think that the ballast works from a solid on signal and you could wire up a direct solution as you are thinking.

I would look into the LCM water issue you may be able to swap a junker LCM and fix the problem proper.

[c-bass]

Twice I've had those symptoms it ended up being the ballasts.

[treeman]

I’ve unplugged the power leads to the ballasts and both read 12v when I’m switching the lights on - this is making me think it is more likely to be the ballasts now as c-bass says.
Shame one doesn’t work as I could swap to test to narrow it down.

Anything to look out for when buying used ballasts off eBay?

[crystalworks]

Originally Posted by treeman

Anything to look out for when buying used ballasts off eBay?

A buyer protection guarantee. Ebay usually offers it with good sellers so not hard to find. If the part shows up DOA you'll get a refund back very quickly so you can try another.

[treeman]

Problem solved!
I didn’t know that xenon bulbs can work intermittently - all bulbs I’d had before (including previous xenon bulbs) either work or don’t. But in this instance they worked some times and not others.
I tried a new xenon bulb and worked fine. Been 2 months now and new bulbs have fixed the problem.
Lesson learnt - try the obvious first!

[wpoll]

Originally Posted by treeman

Problem solved!
I didn’t know that xenon bulbs can work intermittently - all bulbs I’d had before (including previous xenon bulbs) either work or don’t. But in this instance they worked some times and not others.
I tried a new xenon bulb and worked fine. Been 2 months now and new bulbs have fixed the problem.
Lesson learnt - try the obvious first!

Thanks for the update. Yeah, odd they should be intermittent.... They usually change colour, reduce output etc.

I got two new Osram Xenarcs from Powerbulbs in the UK - best deal I could find, even with postage to the other side of the world.

[andrewwynn]

Historically HID will usually dim and change color slowly as they fail. I had a different experience on my new to me e70. It did change color but also failed within hours. The day after I noticed one side turned quite orange it no longer came on.

I noticed this lamp has the high voltage sparker built into the bulb I think. Curious if that is related.

Anyhow, the $110@ for local procurement wasn't going to happen so I found the highest rated 4300K lamps that were off the discount variety and $30 and two days later I had new lamps on both sides (don't ever replace just one lamp unless it's a premature failure situation).

E70s are definitely easier to get to the lamps but will help if you have small hands it's a very tight fit.