Intermittent main beam headlights

[tattoo93]

Hi everyone,
I've searched the archives and search theads and I tried re soldering on the LKM, but I can't resolve my headlight problem. As the dark nights have set in here in the UK, I have to use my lights for my journey to work and back. The problem is that although the main beams come on when I start my journey, they cut out intermittently leaving just side lights on (a bit scary on the unlit country roads where I live). All other lights work including fogs, high beam, side lights etc. Any clues as to where the problem lies?

Many thanks

[Incantation]

maybe the relay itself is finished.. i don't really know what to suggest other than trying to re-solder.. make sure u clean the area nicely as well before soldering

[tattoo93]

maybe the relay itself is finished.. i don't really know what to suggest other than trying to re-solder.. make sure u clean the area nicely as well before soldering
Cheers for that incantation, I shall try again first thing tommorow

All the best

[Paul in NZ]

i had exactly the same problem and it was resolved by resoldering the lkm.I took it to a local auto electrician with the appropriate info from e 34.net

[tattoo93]

Thanks for the info guys.
I took another look at the LKM using a good light source and a magnifying glass this time. Many of the connections were very poor (is this usual or did I get a duff one?). Anyway I've re-soldered more or less all of the connections. The lights have stayed on so far, so fingers crossed.

Many thanks

[Javier]

feed from the LKM trough pins 2 to 21 from left and 2 to 22 from right. Different pads, different relay contacts, same relay coil though.

Note also that signal to energize relay at Low beam request enters LKM from pin 3, so, as both sides go out together, I would carefully check the LKM board path going from pin 3 to relay coil and then from relay coil to pin 24 that is responsible to supply ground bus 31 to LKM. All soldering joins should be verified in this path.

If you keep getting that problem, I'd suggest to solder wire a small wattage bulb to two long cables, so you can connect it to key points in the engine compartment and run it to the cabin. First try lighting the bulb from fuse F11 and/or F10 and go for a ride to see them getting intermittent, if they don't, , you may have a ground issue, but both sides are grounded separately.

If intermittence is in your probe light, yes the problem comes from the power supply (LKM-LKM Relay/Light switch/Fuse F2), I would try to tap the signal in pin 3 of LKM with the probe bulb. May be the funny contact comes from the Light switch or even the F2 socket feeding the light switch.

Javier

LKM Connector picture:

http://www.bimmer.info/forum/attachment.php?attachmentid=886&stc=1