At my wits end with the LCM
 

A few weeks ago my sunroof decided to spring a leak and give the middle connector of my LCM a shower! It drained the battery and caused some lighting faults. (This has happened before :rolleyes: but I believe I have permanently fixed the leak now).

One of the pins at the bottom of the connector had corroded and then snapped off. So I sent the LCM away to have a new connector soldered on and all of the LCM's functionality tested. All ok according to the technician!

The symptoms are:

• headlights coming on with ignition regardless of switch position
• indicators not lighting up on dash but they do flash outside the car
• and a weird one, the voltage no longer displays on the ibus app since this issue! :dunno:

So I fitted the fixed LCM back in the car but the same problems persist! I then noticed that a couple of the pins in the female side of the connector were super corroded and had fallen apart. So I ordered new pins and crimped them on. I thought that would fix the poor connection but, nope! Same problems. :( I've checked all the pins and connections. They all look good!

Does anyone know what, or what wire could be causing these specific faults? Wiring is my least confident aspect of cars. I look at wiring diagrams and I might as well be looking at quantum physics!

I also now have an airbag warning light as the water leak caused my battery to go completely flat for a few days. Can this be cleared using the BMW 1.4 coding software? It's all I have (not even used it yet, complete noob).

Thanks in advance for any help!

This is a tough one, sorry for your issues. But these are super complicated cars. Just for your information-my 03 directionals would work fine, but I had no indicators on dash. Randomly found that my nav. computer in the back was not working and replaced it and all was good again! Makes no sense to me, but telling you so that you are aware of all possibilities

Thanks, Cape. I have replaced my nav with an xtrons headunit and removed the dvd drive in the rear. Is that the unit you are referring to?

Update on this.


12 hours after plugging the 'tested' LCM back in, the battery is completely dead! :dunno::(

Yes, that is what I am referring to. If you can, maybe temporarily put it all back to original and see if it fixes itself.

[wrong thread sorry]

Indicators not showing on the cluster is typical I-/K-bus problem. So if you have any after market units connected to that bus I would temporarily unplug them.

Thanks for the suggestions guys. But now I have a bigger problem to fix first with the LCM draining the battery! :( What could be causing that?

Today I finally got around to trying to diagnose this problem. The car has sat unused hooked up to a CTEK charger for weeks because of this.

I did a parasitic draw test by latching the doors and letting the car go to sleep then testing fuses.

I started in the rear fuse box. All seemed good except F75 which was 20mv across a 5a fuse! I think I found the culprit! F75 says it's 'Audio system, navigation system' so I checked for any loose plugs in the rear of the car where I removed the navigation stystem that might be grounding out. Nothing. I unplugged the xtrons harness that goes to the front of the car. Nothing.

I looked up a wiring diagram but I might as well show it to a dog because he would make about as much sense of it as I can! :dunno:

I don't know what to do next.

Oh and the LCM problems persist. All sorts of lighting issues.

I should note that I bought an identical part number LCM from eBay and plugged it in. Absolutely nothing changed so went back to my original which I believe to be good.

Well I finally figured out what was wrong and in case anyone is searching this in the future here is what the problem was...

I'm retarded.

When crimping on new terminals inside the X10117 connector, I accidentally switched pins 35 and 36! Pin 36 being the k-bus signal wire!

:D

doh!

If you call it "user error" then it sounds less bad

Yeah - that'll do it... :rolleyes:

What does LCM stand for?

Light and check control module.

So happy to have found this tread.
Can you tell me what type of crimp pins you used for the X10117 connector please.

I bought a new connector including the 54 new terminals. I didn't use the plastic part as mine was fine. I just used a handful of the new terminals to replace the corroded ones. I don't know the specification of the terminals themselves unfortunately.

Anyway, it was listed as 4E0972144. If you search that on AliExpress you should find what you need.

I also had to buy a crimping tool to do the job correctly. It's a very fiddly job to do down there in the footwell with very little wire to work with, and the terminals are tiny! Good luck! :D

Good luck!

Sounds like a nightmare :yikes: