Help - door locks won't work?
Teching In
Joined: Jul 2008
Posts: 12
Likes: 0
From: Calgary, AB Canada
Beast_1,
I'd suggest whatever you do -- don't damage what's left of the bcm. Ideally you'll get a working bcm at a decent price but if not -- you could maybe keep it in use and for probably a lot less $$, get an aftermarket car starter which will have door lock/unlock functions (with additional relays to handle the power for the door motors as typically a car starter is only expecting to do triggering lock/unlock).
You might also be able to work around the problem. Each of the 3 wires I mentioned before should either show (+) or (-) depending on lock/unlock and tan vs. grey but 1 of them (or 2 but probably not all 3) does a nothing when lock is requested. A couple of relays (maybe more) to supply the missing (+) or (-) when locking could probably be added to make it work.
I'd suggest whatever you do -- don't damage what's left of the bcm. Ideally you'll get a working bcm at a decent price but if not -- you could maybe keep it in use and for probably a lot less $$, get an aftermarket car starter which will have door lock/unlock functions (with additional relays to handle the power for the door motors as typically a car starter is only expecting to do triggering lock/unlock).
You might also be able to work around the problem. Each of the 3 wires I mentioned before should either show (+) or (-) depending on lock/unlock and tan vs. grey but 1 of them (or 2 but probably not all 3) does a nothing when lock is requested. A couple of relays (maybe more) to supply the missing (+) or (-) when locking could probably be added to make it work.
Finally ID'd problem:
Notice the burned end of this chip. Of course after calling Texas Instruments, I can't buy the part directly because it's proprietary to the OEM.
I've got a used BCM on order... when it gets here I guess I'll decide if I want to pay the dealer $200 to program the new part, or just re-solder the good chip from the old boad onto mine.
We'll see... and I'll keep you posted!
Notice the burned end of this chip. Of course after calling Texas Instruments, I can't buy the part directly because it's proprietary to the OEM.
I've got a used BCM on order... when it gets here I guess I'll decide if I want to pay the dealer $200 to program the new part, or just re-solder the good chip from the old boad onto mine.
We'll see... and I'll keep you posted!
TECH Fanatic
Joined: Oct 2006
Posts: 1,190
Likes: 0
Even if you could buy the chip it still would need to be programmed with specific code before you put it on the board. But since you found the burnt one you probably already know that.
Is there a manufacturer part # on the board that you can see? Maybe even a sticker with the rev level on it?
Is there a manufacturer part # on the board that you can see? Maybe even a sticker with the rev level on it?
Yes, I called TI, and this is a proprietary AND/OR circuit, but they couldn't say more than that. The programming is not on this chip, so I should be able to swap them out.
I should get the used BCM Friday or Saturday... I'll let everybody know how it goes!
I should get the used BCM Friday or Saturday... I'll let everybody know how it goes!
Teching In
Joined: Jul 2008
Posts: 12
Likes: 0
From: Calgary, AB Canada
My 2 cents ($0.03 Cdn)...
IC's don't handle a lot of power; something else is wrong which flowed a lot of current through the IC to fry it. I'm guessing an IC handles less than 1A. The door lock fuse is 15A so maybe all four door lock motors together would draw say 10A.
IC's don't handle a lot of power; something else is wrong which flowed a lot of current through the IC to fry it. I'm guessing an IC handles less than 1A. The door lock fuse is 15A so maybe all four door lock motors together would draw say 10A.
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Well hot damn... nobody is more surprised than myself... but it worked. 
At least it's working for now. And for the record, I chickened out at first and tried to take the easy way out. I took the BCM I got from the junk yard and took it (w/ car) to the dealer for programming... but they said it wouldn't take a program, which happens sometimes even on new units.
I was aware from the beginning that there is a chance another component was actually what fried this one... but given the junkyard BCM was locked, I went ahead and installed the junkyard chip onto my board and for the last 24 hrs it's worked with no issues.
Fingers crossed!
Mark
At least it's working for now. And for the record, I chickened out at first and tried to take the easy way out. I took the BCM I got from the junk yard and took it (w/ car) to the dealer for programming... but they said it wouldn't take a program, which happens sometimes even on new units.
I was aware from the beginning that there is a chance another component was actually what fried this one... but given the junkyard BCM was locked, I went ahead and installed the junkyard chip onto my board and for the last 24 hrs it's worked with no issues.
Fingers crossed!
Mark
Last edited by Beast_1; Oct 21, 2008 at 07:21 PM.
