Franklin Junior

I have a 2007 GMC Sierra 1500 SLE (not the classic) But I’m having issues with It. has the 5.3 motor. I was driving down the highway and when I got off the highway The truck decided to engage the four-wheel-drive basically by itself when I was making a turn and it felt real sluggish so I pulled over shut it off to see what was going on and I didn’t see anything. When I went to go start it again it didn’t start and the only gauges on the cluster that worked was the battery voltage. After hooking up a scan tool it wouldn’t communicate at first and then miraculously it worked for a few seconds to give me the U0073 (unable to communicate with bus A) and then it stopped working shortly after that. After inspected simple things and what have you, I narrowed it down to the TCCM (transfer case Control Module) I disconnected the middle brown wire connector and everything worked again including letting me start it and even putting it in gear and driving a little bit. (Only drove it a block without coming out first just in case i would cause more issues) but as soon as I plug it back in the issues arise. The scan tool will communicate when it’s unplugged and give me the same u0073 and it also gives me unable to communicate with TCCM (Most likely because I disconnected the connector to it) and a unable to communicate with fuel pump control module code as well. (Truck does start though so I think that’s just a side effect code but not sure) and that is it. I should also mention that I replaced the tccm as well after I figure all this out just in case it was the module. But still no luck... does anyone have an idea or could someone find me a diagram that tells me what that brown connector does or where it goes to so I can check the other end? Any help is appreciated!!!!