the gm trucks have a shutdown current flow around .25 amps and lower. the truck shuts down then 15-20min and then see if the current ..
now you did a few fuses pull it out then the BCM could be an issue ..or see if the door switches are not working ..
look up the engine rear next to the firewall then the GM ground strap corrodes..

 

Last year I bought a 2001 Yukon that had a known about parasitic draw on the battery. It was a pretty new battery but if you didn't run it every day it needed a Jumpstart. There are tons of videos on YouTube that can give you a few places to check for grounds that have gone bad and for components that are known for issues like spedo-gage clusters experiencing silver migration from the lead free soldering. My eventual solution was to installing a 250 amp alternator, and a second battery under the hood and hook it up full time. Parasitic draw that overnight.

 

my 2000 silverado I would not use it a week later then start it .. starts good .. I have the alternator 105amp and a 800amp battery ...
you should look up the shutdown current flow use a amp meter see if the current is over .25 amp/ 250ma ..then the battery are loosing the power ..

many have a high powered audio amplifiers your should install it .. with your high current power on the amplifiers ..

 

I went way overboard for a reason, I've installed a 3500 watt pure sine wave power inverter and a 3 battery bank. It's all charged by the alternator with a cyrix intelligent battery combiner. I can monitor the current flow and starter battery voltage. Check out the Victron Bluetooth smart shunt, coolest gadget ever 😎. I'll add some pics of that soon.

 

Well my 2003 Silverado, was solved (so far) by instr panel replaced/additional gnd strap FW2eng/new batt .... it was intermittently draining batt for years, each fix would last a week or so then start up again, this last fix was the second instr panel, its been good for last 5-6 weeks!, keeping fingers crossed lol.
But now ever since inst panel installed my bck up lights and middle tail lights don't work! ... bulbs good, fuses ok, so not sure what now?? maybe wiring harness to rear??🙄

 

Ugg, I had bcm replaced and that didn't fix my display or courtesy lights. My best guess is that aftermarket remote start and passlock bypass are part of my draw as well as possible bad grounds. Project truck ...

 

Bad grounds won't contribute to a battery drain, poor grounds are opens and current won't flow through an open.
However, there is a possibility that an open ground could cause a data LAN hic-cup, if the LAN can't communicate a system shut down (go to sleep) the awake systems will drain the battery.

But, this condition should throw a trouble code, lighting the CEL.

 

As promised a couple of pics of the battery combiner and smartshunt connection. I can monitor the power in the battery bank and voltage for starter battery with my phone. The combiner allows me to use the battery bank for a Jumpstart at the push of a button.

 

Good setup. We'll consider that when we start working on my uncle's 2001 GMC Yukon project with a mysterious parasitic draw. We'll just finish installing the new rotors and black rhino wheels on the Silverado this week before we can take her in.

 

Oops, I didn't mean to load the pics 4x

 

This conversation is a year old, but here goes. I have the identical problem as the OP, starting to think it's the bcm. Curious what the OP found out. Thanks.

 

Okay, as stated above, I have the identical problem as the OP. I was thinking the bcm was the issue, but now leaning towards the fuse box. Mice moved in there over the winter and left plenty "signs" behind. Corrosion on the underside of the fuse box? I'm thinking that replacing it would be a pain, but may need to be done. Any comments? Thanks in advance ~ Bob

 

DID YOU OF THE POSTING , OF YOUR TRUCK ...
the mice is a nest of under the winter of the engine fuse box ....maybe !

 

If it's a '07 to '13, good possibility it's corrosion.

I've changed 2, not a big deal.

 

It's an 04, should be similar I'm guessing.

 

My 07 Classic Duramax had a similar problem. There's something in the instrument cluster that power must go through. I had my cluster rebuilt and problem went away. A dealer tech told me if you drive with the cluster removed, the battery won't charge.
Bob

 

I drove my 2004 1500 for a year with the dash cluster removed and everything works just fine. I just kept forgetting and procrastinating on sending it in to get fixed. Because mine didn't work anymore. Also didn't fix my parasitic draw... still don't know what it is. I was bummed it didn't go away when I removed the cluster initially.