GM products are not my bag, but I would follow the biggest, ugliest wire harness on the car, it will lead you to it.
How much??.......who knows?, but I would search wrecking yards inventory before shelling out probably big $$$ for a new one.

 

Well I left the batt 1 fuse out all day then went out and put it back in and car started. So now the question is what runs off that fuse? I've Google it and can't find an answer.

 

Sorry just got back . Batt 1 fuse feeds the entire fuse panel on the right side of the dash .

 

13 fused ckts , 22 branch ckts . Feeds a bunch of things !

 

So how do I figure out what is drawing from that fuse

 

You need to obtain a schematic from some source and once you identify the items powered by it, you start disconnecting them one by one and re-connecting until you find the one that goes ZAP when you re-connect (there's the heavy draw culprit)
A ohm meter and a voltmeter are your friends.

 

Have you pulled those fuses one at a time ? have you waited 25 min for moduels to go to sleep ?
You need to use a DVOM set on amps to properly test if you do not have an amp clamp .

 

even a fuse buddy would do in this case .

 

Fuses supplied by that are as follows . Air bag , canister vent ,inadvt. pwr ,Ctsy , Infotainment , Dsplay ,radio , amp ,MSM ?, power mod , and last but not least BCM !

 

Did this vehicle have a aftermarket alarm or "big thumpin" stereo installed off this fuse?

 

#ad

 

^ 6 at the top is batt 1 feed .

 

Not sure how to read that. If I had a list of what runs off batt 1 fuse I could start unplugging

 

I see 11 things at top so not sure which ones