Central Locking Problems

[Butler]

Im in the middle of trying to fix my centra locking issues right now. I had really high hopes that I'd find the answer by them end of this thread! :( Fucking annoying. Its freezing cold, my kick panel broke into 10 pieces when I pulled it out, and I still don't know whats wrong with this thing!

Its weird because Its worked beautifully for years now. One day I was driving home and the drivers door started locking and unlocking itself for about 45 seconds until it died. Since then my CL has been non existant.

/sucks

[rav320uk]

Was there any buzzing sounds coming from the C/L ECU?

[jeffnhiscars]

I've got to stick my nose in here with a question. Last week I rebuilt my drivers door lock so now that is working as it should. Today I swapped the known good relay and clcu from my other car and confirmed it was the CU. Just for fun I pulled the cover off and found the thermal fuse melted..bingo !! Resoldered it, put it all back together and it worked fine at least for a while.

My problem now is the door actuators are in lock, but none of the doors are locked and the key will not even turn as if to lock them. I think its a synch issue but can't seem to get a response from the system.

[rav320uk]

When you "Resoldered" it, did you use NEW solder?

[jeffnhiscars]

When you "Resoldered" it, did you use NEW solder?

Of course, after de-soldering the old....but I doubt that would have anything to do with why the actuators are stuck

[Butler]

Was there any buzzing sounds coming from the C/L ECU?

When it went bad I was driving and couldnt hear anything from down there. I can hear the CL unit click while Im unlocking the car.

[rav320uk]

Of course, after de-soldering the old....but I doubt that would have anything to do with why the actuators are stuck

That's the problem, the solder you used has a higher melting point, the origional one BMW used had a lower melting point, hence why it was cracked.
This is so that the rest of the C/L is saved if there is an electrical issue elsewhere!

What you have done is allowed more current to flow to the C/L, and I think you may have fried your actuators, as that's always the first to go when its soldered with high melitng point stuff.

[rav320uk]

When it went bad I was driving and couldnt hear anything from down there. I can hear the CL unit click while Im unlocking the car.

Is the inside of the footwell dry??

[jeffnhiscars]

That's the problem, the solder you used has a higher melting point, the origional one BMW used had a lower melting point, hence why it was cracked.
This is so that the rest of the C/L is saved if there is an electrical issue elsewhere!

What you have done is allowed more current to flow to the C/L, and I think you may have fried your actuators, as that's always the first to go when its soldered with high melitng point stuff.

Valid point & it confirms that the CLCU is bad beyond the melted thermal fuse...and yes, it wasnt too bright to think I could just resolder it and not deal with the underlying cause..although you would think there is some other form of protection (like a fuse) to keep the actuators from frying

I'll swap back in my known good CLCU which will tell me if the actuators are ok.

TY

[jeffnhiscars]

So I put the good CLCU in the non-working car and it did not help. I then put the CU back in the working car and swapped in the trunk actuator from the non-working car and it is confirmed fried. I also read on e30wiki that when the actuators fry they default to double lock which means your key is useless until you remove or loosen the actuators. Precisely where I am at.

Note to self...do not bypass thermal protection ever again !!

[rav320uk]

Leson learnt:p

[jeffnhiscars]

Leson learnt:p

The good news is, I got a CLCU and 4 actuators from a friend of mine and in less than 2 hours I have a perfectly functioning locking system as well as sound deadened doors.

Lesson learned

[Butler]

Is the inside of the footwell dry??

Yeah it is