central lock unit guts

E28 technical advice asked and given! Troubleshooting, modifications and more.
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pdx 528e
Posts: 3034
Joined: Feb 12, 2006 12:00 PM
Location: Idaho Falls, ID

Post by pdx 528e »

I've been troubleshooting for a couple days. I opened up my control unit.. and I found something that looks like it used to be soldered. Has anyone opened one of these up, and can confirm that I should solder this? My camera doesnt do closeups very well.
Image

At wits end, I dont think I have much to lose here.

Thanks in advance
Chris
Bob in San Jose
Posts: 139
Joined: Feb 12, 2006 12:00 PM

Post by Bob in San Jose »

Chris,
Looking at the picture it appears to be an inductor. You can try soldering it but I doubt you will have much luck.
Is there any numbers or printing on it?
That might tell what value it is and you can get a replacement at an electronics store.
I think I have one of these units in my spare parts cache. Give me the BMW part# off it and I'll check if it's the same one.
Blue Shadow
Posts: 10286
Joined: Feb 12, 2006 12:00 PM
Location: SE PA

Post by Blue Shadow »

That is supposed to be soldered. There are places on the web that say so. It is the safety automatic unlocking for severe impact and over use of the knob. Remember the manual says only lock and unlock a few times to avoid problems
pdx 528e
Posts: 3034
Joined: Feb 12, 2006 12:00 PM
Location: Idaho Falls, ID

Post by pdx 528e »

[QUOTE="Bob in San Jose"]Chris,
Looking at the picture it appears to be an inductor. You can try soldering it but I doubt you will have much luck.
Is there any numbers or printing on it?
That might tell what value it is and you can get a replacement at an electronics store.
I think I have one of these units in my spare parts cache. Give me the BMW part# off it and I'll check if it's the same one.[/QUOTE]

I refer to this as the central lock control unit. My ETK cdrom calls this an emergency switch, and the part number is 61 31 1 381 788. This unit is in the 82-84 model year setup, meaning no double lock deadbolt, so I think its also a bit skinnier than the 85-88 units. Out of curiousity what does an inductor do in this type of circuit. I know that the electronics for the item include a lock relay, unlock relay and a G force sensitive switch to unlock doors in a crash. Thanks for the reply.

Chris
pdx 528e
Posts: 3034
Joined: Feb 12, 2006 12:00 PM
Location: Idaho Falls, ID

Post by pdx 528e »

I cant believe it, but soldering that loose joint completely fixed my locks. Nothing else needed attention in the entire system. I will leave that image up so that it can be found in the archives or whatever. Onward to keyless entry... or should I get an alarm while im up to it?

Chris
Blue Shadow
Posts: 10286
Joined: Feb 12, 2006 12:00 PM
Location: SE PA

Post by Blue Shadow »

Glad we got you locking and unlocking again. Now that we have your pic an write-up I don't need to find the link. We can stand on our own. Nice work. I ask RonW when I need to know electrical stuff and don't know the answers you seek.
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