Awhile ago my heater core let go. I took the car apart couldn't get the hvac unit out . Then I put it all back together and yep fill the floor pan full of coolant .so took it all apart again and with some searching on the forum and internet I found the one bolt that was holding it in . So I replaced the heater core and I thought I had all of the coolant cleaned up and all was dry. But nope smoke roll from the BCM . I took it to work and the guys there put a diode in . That all they found burned up , but with my luck still no start. Before I buy another BCM is there something else I need to check first that I'm missing my car is a 99 c5

 

Did the Bcm get contaminated with coolant? We need more info. Did everything work right before you took it apart? If a wire got pinched during reassembly, you might smoke the new Bcm.

 

Yes the BCM got wet with coolant .all worked good until I seen the smoke coming from the BCM now the radio will not work and I can hear the fuel pump prime up but the car will not turn over

 

I've always heard that if you let the smoke out they're done.

 

Did you make sure the Fuse box was dry before you powered everything up? Also, you may have gotten water into the 2 Serial Bus Star Connectors right there by the BCM. Here is what they look like. You most likely need to have your BCM repaired or replaced. Not sure how your local guys can verify the things you "can't" see in the internal design.

 

Yep. All sparks run on smoke.

 

I am sure you need another BCM or send that one to Cardone to see if it can be fixed. I doubt a single diode would have caused enough smoke for you to see.

With that, here are the fuses that provide power to the BCM that may be blown. I included the grounds but they should be OK.

BCM +12V power feeds from I/P fuse box
Fuse #25 = BCM Logic Power Feed (Powered all the time)
Fuse #23 +Power feed for 12V BCM Drive outputs (CL)
Fuse #13 = 12V switched from ignition switch (ON, and START positions)
Fuse #9 = 12V from Ignition switch (ON and ACC position)

BCM grounds
A9-C1 connector pin Logic Ground
A2-C3 Power Drive Ground
G104 & G202

If you want to discuss on the phone you are welcome to PM me with your number. If you make sure the Star Connectors and the fuse box are dry and put in a good BCM you should be good to go. There is a chance you got voltage onto the Serial Bus and that took out communication needed for certain modules to operate in concert with others but I hope not. The IPC acts as the "Fuse" for voltage on the Serial Bus and should protect all the others. Anyway, let's not get to far ahead of ourselves. If you end up with Serial Bus related issues we can figure out where it is, not difficult.

 

Pull out the interior fuse box and check the connectors for rust or corrosion, especially the lowest one. Good luck.