I'm thinking its the BCM Body Control Module possibly

 

I doubt it. They very rarely fail. Is the vehicle equipped with OnStar?

 

Not that I am aware of.

 

If the rearview mirror has no buttons, it doesn't have OnStar. I brought it up because the OnStar module has an emergency mode built into it that gets permanently switched on if the ignition is turned on (to the RUN position) while the main battery is disconnected. This causes a parasitic draw that will drain the battery overnight.

If your vehicle doesn't have OnStar, then it's not a factor. As it stands now, if the battery drain stopped when removing the Radio fuse, I'd guess the radio is bad.

 

Battery was dead this morning so I took out the fuse and it took a jump. I ordered a new radio, hopefully that's it.

 

There are a handful of fuses to check, fuse 9, 10 and 30 in the dash fuse block. If those are good then need to consider that a logic error may have occurred and a reset is needed.

Take the battery cables off the battery, hold the ends together for 10 seconds then attach them to the battery and see what happens. This will reset the whole vehicle.

If these steps do not fix the issue then I believe it will need a software update and that is only able to be done at a GM dealer.