BCM will not finish programming
 

Got a new BCM and brought to a dealer to get programming because the old one shows the airbag light and abs trac light and is drawing amps killing the batt. so Tried getting done the first time they said it would not connect. found some loose wires that I resoldered and brought the chevy back and they could connect this time but it would not finish the program. it went to the end and wouldn't finish for some reason. now I told the dealer that the wires may need to be jiggled but still to no avail.

So what else can be the problem? it still could be something wrong with the wiring, because the Driver information center on top isn't working but that could be attributed to the BCM not working correctly right? it works fine except for the airbag light and drawing amps when off. but i noticed some other things staying on when off light the hvac blower can but turned on with the knob and the recirculation light stays on, but when I turn the key more off it turns off but it doesnt click you know? it's like a slight pressure towards off and then it turns off.

does the stock radio need to be installed?
what can I do to have the bcm programmed? anything about the pcm. ecu? it was reflashed once I believe to put in the Vin when engine swapped with a supercharger?

2000 Monte Carlo SS. Got this used that had an engine and transmission swap. it has an L67 now, or really an L36 with supercharger and a 4t65e HD transmission for a 2003 or 2004 gm. I believe the previous owner swapped parts from a 2003 grand prix.

I noticed the bcm connection wires were cut and spliced back together. was this something he did on purpose to get the pcm and bcm to work together? anyone know anything about this?

Sorry to hear, sounds like a real basket case. Honestly, its going to be hard for anyone to speculate what could be wrong, especially given that it sounds like it was pretty hacked up.

Personally, I'd find a junkyard with the same year car with a 3800 and the same interior options and take the pcm, bcm, and wire harness. No doubt that's a ton of work, but at least you know itll work. Itll save you from spending a ton if time trying to undo someone else's hack job.

I am with Bumpin'. You mentioned a few things that ring to problems:
- L67 swap. This is NOT an end all, it's pretty common for people to do. But this is the first jump beyond the factory spec for the car. BUT, this should ONLY affect the PCM part, NOT the BCM.
- You mentioned the lose wiring and splicing around the BCM. Why was any of that wiring spliced? Obviously the discovery of BAD splices says who ever did the work was not very skilled.

It is really hard to say what is going on that is interfering with the communications between the computer systems in the car. I am going to recommend you find a local shop (maybe the dealer ship) that is familiar with this platform, hopefully familiar with an L67 swap, that can help determine if the wiring is actually correct.

Agreed a couple bad splices and incorrect resistance could shut down a needed step for the bcm to proceed.

Also think a 2003 transmission will not typically work in a 2002 or lower model year. Something was spliced together there to make things work and perhaps hindering the bcm from completing its systems check

IMO, I think the dealer would be near useless and / or obscenely expensive in this case mostly due to how modded it is. In my experience, they usually don't want to touch something that's heavily modded, especially with stuff they dont understand (ie an engine swap vs just a catback exhaust).

Back when I used to work at Circuit City in college in car audio, there were numerous times we had to uninstall aftermarket stuff before they'd touch it and then had to reinstall after - even if the issue was on a totally unrelated circuit.

I also remember people trying to take their L67 swap 5th gens to sort out issues from the swap (back when it was still new) and most got turned away and would just end up back on the forums trying to work through it themself.

Probably right about the dealer. I think no matter where it is taken will be a costly venture.

No doubt, unfortunately that's one of the big downfalls of major mods like that. Most shops get enough business doing stuff they know, stuff they've done before, and stuff that has a clear book time. It's easy to price jobs like that and stay profitable.

Getting into a mess like this where someone has hacked it up, and you have no idea what you're getting into is very risky for them. They could burn a whole day at $100/hr, still not have all the issues sorted out, and now have an irate customer because theyve sunk so much money into it. A shop would either have to be somewhat desperate for work or they'd just gouge the heck out of you to ensure they make some profit in the end. Sadly, I think that's a reason why some of the early 5th gen L67 swaps ended up sold / junked.