Only one low beam working.

[FrankC]

I noticed yesterday that my low beam drivers side was not working. Its an H1S HID unit in there. With the balast fixed to the rear. So I bit the bullet, they are very expensive, and ordered a couple of new ones.

They arrived today so I stuck it in there................. Still not working. Tried the other new one............... nothing.

I think the fuses for the low beam are in the engine bay box, 10 amp? Checked all the 10 amps, could not see any numbers as I think its fuse 6 or 9. So I simply checked all the 10 amps. All seem fine.

I do not have a meter.

Suggestions?

[mike020150]

Without any diagnostics, life these days is difficult. have you tried swapping the burners (bulbs) between headlamps to see if that is the root cause of the problem? Mike.

[FrankC]

I tried two brand new bulbs in there. All the same I am going to put a new one in the side I know is working, just in case. I think its a wiring or fuse problem. Fuse 6 or 9 in the engine bay fuse box? Problem is the fuse positions do not seem to be marked.

Thanks for the reply.

[FrankC]

Just been out again. Took out the working bulb. Then got the new bulb that would not work on the drivers side. Put it in. Works. So it must be either a fuse or wiring.

[andypryce]

Check any earthing points nearby, had exact same issue on my X350 and was the earthing point behind the lamp.

[FrankC]

Thanks will do. Just had a thought. Perhaps I will try a wire just touching the rear of the ballast and the other end connect to earth..........

Other things I have done. Checked fuse 6 20amp. Its fine. Swapped over relays put another working one into 5 slot, still not working. Will give that earth idea a go though.

[andypryce]

Be careful though, they operate at high voltage I believe.

[FrankC]

Nope Even earthing the rear has not helped.

[andypryce]

can you check for voltage supply with a voltmeter? Does sound like no power to it then, in which case I guess a question of working back from the light until you get voltage, pain in the butt though...

[FrankC]

Looks like a garage job. The wheel needs removing and the liner to gain a bit more access to the wiring. I have emailed the company that supplies the OEM leads from the H1 bulb to the supply. May have to buy one of those and work out how to fit it. Such a confined space.

Thanks for the suggestions Andy, keep em coming

[andypryce]

Agree sounds like a garage job, unfortunately. Yes the access is awful. Let us know how you get on.

[FrankC]

Thanks Andy, yes I will.

Had a reply from the wire company. Interesting 'English'

"Hello Frankc

Yes we have you need part

can you tell me how many do you need this ?

Sword"

Also emailed my garage. I have faith that they will sort it.

[andypryce]

pretty much guarantee that if you order that part from then, it won't be the one you want!

[FrankC]

Progress.

First off that email I copied on to here. I think its a con. I had a very similar email when I was looking for a bonnet liner. Same sort of wording and exactly the same price quoted. £65. They also seemed very interested in my paypal and credit card details. Steering clear I think unless anyone on here has used them?

Anyway back to the Progress bit.

After much checking. Pulling connectors off etc I finally tracked the feed wire for the dipped headlights going into a large connector on the back of the headlight system. When I switch on the dipped beam this wire goes live! So I know the feed is getting to the headlight system. So somewhere between this connector and the dipped beam is a bad bit.

I also noticed though that the auto leveling does not work on this side. So I now have to work out which wire runs both the headlight and the auto leveling. As the main beam works I am assuming that the same earth is used by dipped and main beam so I can rule a bad earth out? Unless the wiring runs from the dipped beam to the leveling I may be able to discount a loose wire in the rear of the dipped beam connection.

Any links to the auto leveling wiring system? Got the main wiring for the HID system but no detail in the actual leveling bit.

So suggestions as to what to check next?

[andypryce]

Have you checked the actual plug that goes into the HID unit itself? If that is live then it has to be an earth issue. As to the self levelling bit, no idea, sorry!