Ok guys,here's the issue Ive been dealing with.
I few week ago (4th of July weekend), I started experiencing an issue with my Tahoe. It cranked and started,but got a service brakes warning. I drove it a few miles,and it started acting like the trans wasn't down shifting. I could manually shift it though. Stopped at some friends house shut it off. Cranked and started again a short time later,and drove home (few miles).
Next day got in it to go to store,it cranked and started. While letting it cool off (very hot here in Texas),my wife shut here door,and a/c shut off and engine died.
Tahoe will now not crank over. Door locks and windows work,a/c doesn't.
I can jump starter relay,and It will crank and stay running.
A buddy of mine came over and put his scanner on it,and didn't see anything weird.
I replaced the ignition switch..nothing!
Installed a passkey bypass (New Rockies)...nothing!
So any help of how to fix it or where to look would be appreciated.
I'm fearing it might be the BCM,but I don't want to buy one for $320 and that not be the issue!
Please help,or at least tell me who might know what the issue is.

 

Welcome to the forum...
Might want to check the battery cables, both ground and positive cable...
put a meter on the starter cable and have someone crank it over and see what kind of voltage drop you are getting at the starter...should be pretty minimal from what you get for a reading at the battery....