billbled

So I checked at the connectors on the BCM today, and testing from ground on the connector to power on the same connector, I had battery voltage. This is on connectors X2, X3 and X4. Based on this I'm calling power and ground good to the BCM, and thinking that the BCM has gone bad. It's weird - the sequence of events that led up to this: 1- Check engine light was on - unknown code - he doesn't have a scan tool. 2- My friend was trying to clear it by disconnecting the battery. He disconnected the positive lead of the battery and left it off for 4-5 days (had other things going on and forgot about it). 3- He comes back and re-attaches the positive lead, and noticed the interior lights are not on with the door open. 4- Tries to start the truck and zero. No click, no starter, nothing. Plus, now he's got multiple warnings in the instrument cluster to service different systems and things that are offline. All this from just leaving the positive cable of the battery off for a few days. Kind of blows me away that a BCM could (apparently) go bad just by being powered down for a few days. Truck has about 150k miles on it and is in pretty good shape and has been maintained well. So do you all agree that it sounds like the BCM is bad? Any ideas as to why the BCM woulda quit, after reading the sequence of events that led up to this? Opinions? thanks much, Bill

Thanks - I've got access to Mitchell's at work - I hardly ever use it since I'm usually in other things, but you've reminded me it's there - I'll check it tomorrow.

I am - thank you very much. I've got them downloaded, opened and printed. Looks very helpful. I'm going to get back on this over the weekend. Cheers!

Hi, I'm working on a friend's 2007 GMC Sierra 4WD, and it is not starting and not cranking. I brought the Snapon Solus Edge home from work and ran codes. U0140 and I can't talk the BCM at all. Fuses on the LH side of the dash are good for feeding the BCM. I keep hearing about a fusible link? (Sorry - I'm not real familiar with GM stuff). I've read that it supplies the BCM. Can someone give me a clue where that would be on this truck? Thanks much from a newbie. --Bill