2012 GMC 2500HD 6.0l battery drain

08lmm72mm

Active member
May 13, 2019
537
168
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Saskatchewan, Canada
Hey I'm working on a work truck that has consistent had battery drain and I'm tasked to figure the issue out.

With the negative cable unhooked from the batter and a MM in-between with the key off and out and doors shut there is a 2.79amp draw. I've pulled every fuse there is, I found:

#42 RDO this one is drawing about 1 amp. it isn't going to sleep even after a couple hours. So the radio unit is defective.

Info fuse 10A in beside the drivers door probably for the cluster dic, pull that one and it's down another 0.5a .

Now sitting and 1.3amps.... pulled every other fuse there is on the truck and left bussed electrical center 1 pulled brings it down to 0.8a, pulled left bussed electrical center and it's down to 0.6a .

So what I'm scratching my head at is I know the radio is defective, but why am I getting draw from #22 for the dic and #64, #72 LBEC 1 & 2?

I've read others diagnose this EXACT problem to a T like I've posted but the trail ends, the solution never gets reported.

Any advice where to go next?
 

Ron Nielson

Active member
Oct 11, 2009
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Berryton, KS
Sounds like the truck really isn't asleep. If you want to find out which circuits are problems, check both sides of a specific fuse, one voltmeter probe on one side of the fuse, the other probe on the other. If there is amps flowing thru the fuse, you will see the voltage. If no voltage, no amp flow; time to move to another circuit. Now, If your draw is intermittent, you may miss something - this only works when there is currently a draw happening. Radios, cig lighter, anyhing aftermarket plugged into the DLC (so that means anything plugged into the DLC) are prime places to look for draws. Once you have eliminated those, move on to something else. Having a wiring diagram and using it is like driving across country to a place you've never been to before. Way easier to reach your destination than just tryg every road.
 

08lmm72mm

Active member
May 13, 2019
537
168
43
Saskatchewan, Canada
Sounds like the truck really isn't asleep. If you want to find out which circuits are problems, check both sides of a specific fuse, one voltmeter probe on one side of the fuse, the other probe on the other. If there is amps flowing thru the fuse, you will see the voltage. If no voltage, no amp flow; time to move to another circuit. Now, If your draw is intermittent, you may miss something - this only works when there is currently a draw happening. Radios, cig lighter, anyhing aftermarket plugged into the DLC (so that means anything plugged into the DLC) are prime places to look for draws. Once you have eliminated those, move on to something else. Having a wiring diagram and using it is like driving across country to a place you've never been to before. Way easier to reach your destination than just tryg every road.
That's what I'm thinking the radio and gauge cluster won't go into sleep mode.

I've narrowed it down to a select few that are drawing amps.

Started out at 2.79amps

Removes RDO fuse down to 1.8amps
Removed Gauge cluster 1.5 amps
Removed HVAC Control cluster 1.3amps
Removed LBEC 1, LBEC 2, and airbag batt fuse

Now sitting at 0.07amps .

I have the radio and onstar module completely unplugged from the truck and if I plug in the RDO fuse I gain 0.25 amps.

Very frustrating.
 

660catman

Active member
May 18, 2021
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How about remote start feature? Never had issue with my trucks but did have issue in a snowmobile.


2013 Sierra SLE 2500HD Crew Cab
 

08lmm72mm

Active member
May 13, 2019
537
168
43
Saskatchewan, Canada
We took every fuse out including the main board under the hood and reassembled. So far so good, maybe we fixed the issue without realizing it who knows. Going to let it sit for a week and see if it starts.