Looking for wiring schematics for 1990 535i

[artemis626]

Hi,
I was referred to this site from the bimmerfest site. Someone suggested that Javier mught be able to help me out. I've justpurchased a 535i and my headlights are not functioning. As I understand this is a common problem.

We've checked the connections and the relays. The lights function when the LKM is physically pressed down but otherwise no. We suspect it's a bad wire somewhere. I've been trying to find schematics for the wiring. Can someone here refer me to a site for this or shed some light on the subject? Thanks


here's the link to my original question. http://www.bimmerfest.com/forums/showthread.php?p=1884119&posted=1#post1884119

[SharkmanBMW]

Welcome! Glad you made it.
You are MUCH better off here, there are NO answers over there unless it is a bimmer.info member that replies!

[DaveVoorhis]

The lights function when the LKM is physically pressed down but otherwise no. We suspect it's a bad wire somewhere.
The bad "wire" might be inside the LKM. See http://www.bmwe34.net/E34main/Maintenance/Electrical/LKM.htm

[jrobbo]

I agree, this is such a common problem, it is almost guarenteed to be the LKM.

You need to take out the LKM, and resolder all of the joints on the 4 main relay's near the connector. For good measure, it's worth resoldering the whole board. Should take less than an hour all up

John

[artemis626]

Hi, thanks for the welcome.

We've read about the soldering but from our inspection the board looks fine so we haven't attempted to resolder anything and have looked elsewhere. We've just pulled out the fusebox to check underneath it. Still nothing. This is rather frustrating.

Is it really that that soldering is the main fix for this?

[jrobbo]

What have you got to lose by trying it? The other thing to check is that the 4 relays themselves are not sticking, and are making contact, but i've fixed 4 of these now and it has always been the solder joints

John

[DaveVoorhis]

We've read about the soldering but from our inspection the board looks fine so we haven't attempted to resolder anything and have looked elsewhere.
You inspected it with a microscope? The cracks may be too fine to be visible by the unaided eye. They certainly were on mine, so I confirmed the problem by popping the lid off the LKM and installing it. Poking the relays made the lights flash. Resoldering fixed it.



Is it really that that soldering is the main fix for this?
Yup.

[Javier]

messing with it fixed the lights! Trust the people in here.

You have no registered e-mail, so couldn't sent you 1990 Heads diagram.

Javier

[artemis626]

I've managed to convince my brother to follow the advice from the board. We'll be soldering tomorrow. We were not trying to disregard the advice given here. It was just his honest opinion from inspecting the relay that soldering was not necessary. Hopefully I'll have good news to report tomorrow.

Javier, I did not realize my email info was inaccessible. I have changed that. Thank you for you efforts at contacting me.

[artemis626]

thanks everyone, we got the headlights working. :)

Javier, I got your email. thanks a lot.

[DaveVoorhis]

What did the problem turn out to be?

[shogun]

I agree, this is such a common problem, it is almost guarenteed to be the LKM.

You need to take out the LKM, and resolder all of the joints on the 4 main relay's near the connector. For good measure, it's worth resoldering the whole board. Should take less than an hour all up

John


U.S. LKM's have only 3 relays instead of the rest of the world.
Fog lights front, low beam, high beam.
And in AUS and other countries an additional for the rear fog lights, which they do not have in USA.
Here a U.S. one
http://www.e32fixes.com/results.asp?method=show_fix&fixid=1


and here one from a German version
http://www.7-forum.com/forum/showthread.html?t=52455&highlight=LKM

NR = rear fog light, NS = front fog light, F = high beam, and A = low beam

[artemis626]

What did the problem turn out to be?

Resoldering the relays as had been advised on this board and others seemed to solve the problem. The lights work now and I'm happy for that.