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mike switzer
mike switzer,
Category: GMC
Satisfied Customers: 416
Experience:  lead diagnostic tech at Aamco
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Daniel, I have a battery drain. Ive isolated it to the radio

Customer Question

Daniel, I have a battery drain. Ive isolated it to the radio fuse circuit in the distribution box under the hood. This fuse feeds the radio, hvac switch, instrument cluster and I think the bcm. If I take out the instrument cluster and radio, the problem goes away, but, either one of them, if installed, will pull about 4dcvolts with the key off and out of cylinder. It only takes 3 days to drain the battery. On the internet, this seems to be a commonn problem. Any ideas?
Submitted: 6 months ago.
Category: GMC
Expert:  mike switzer replied 6 months ago.
this is a common problem the guage clusters are more common then the radios. now you said it pulled 4 volts what you need to look for is the amperage that it pulls for a parasitic draw.
Customer: replied 6 months ago.
I tried a different instrument cluster, same result. I put a new radio in it which is compatible. Heres the thing, with the istrument cluster out, radio in, I still get a parasitic drain. With the radio out, instrument cluster in, I get a parasitic drain. With both out, no problem! Actually, its 4 amps, not 4 volts. I took the neg cable off the battery terminal and put my multimeter in line and set it to amps. It draws right at 4 amps with the cluster or radio in it. Without them both, mili amp.
Expert:  mike switzer replied 6 months ago.
wow that is a lot of amerpage draw. now when you plug the radio or cluster in are you waiting 5 minutes for your reading because both are modules and when you plug one in it will draw quite a bit until it shuts down.
Customer: replied 6 months ago.
Not exactly. Ive tried putting one in at a time and leaving it sit for several days. Both will drain the battery down.
Customer: replied 6 months ago.
Ill do another check tomorrow with meter. It has been a while since I checked it. Its really frustrating! Any other possibilities?
Expert:  mike switzer replied 6 months ago.
ok well that is telling me that the vehicle is not shutting down. they have lots of problems with the bcm. i have even seen the entire fuse block be the issue. but more than likely it is the bcm that is causing this.
Customer: replied 6 months ago.
So, it takes 5 minutes to power up the computer in the radio and cluster. I tried a different bcm also! Which fuse block? Under the hood? And, if it was the fuse block, why would it be ok without the radio and cluster? I wish the manufacturers would build simpler circuits!
Customer: replied 6 months ago.
How long does it take for the bcm to power up? Maybe I didnt wait long enough. Actually, I unplugged all the connections at the BCM, and still had battery draw.
Expert:  mike switzer replied 6 months ago.
the reason i say fuse block is because it routes the power and ground it can be okay when remove both the cluster and radio because they break the circuit. not to mention the cluster controls all the interior lights as well. i had a fuse block that made the wipers run at all times even with the switch un plugged the only way to stop them was either remove the fuse or unplug the motor itself. it usually takes the entire car 5 minutes to power down. and go into sleep mode sometimes 10 minutes.
Customer: replied 6 months ago.
I drove it saturday, and today,the battery was flat!
Customer: replied 6 months ago.
If it is the fuse block, would that mean wiring harness also?
Expert:  mike switzer replied 6 months ago.
yeah you definitely have a hard short for it to be pulling 4 amps. give me a moment and i will pull up a wire diagram for that fuse circuit. you will need to trace some wires. no the fuse block unplugs from the harness. it is a fairly straight forward removal.
Expert:  mike switzer replied 6 months ago.
what engine do you have in your 2500?
Customer: replied 6 months ago.
good! 6.0 with 4L80 and manual transfer case, manual windows and doors
Expert:  mike switzer replied 6 months ago.
this are the only two diagrams i can find that include the radio fuse in the diagram.
Customer: replied 6 months ago.
Thanks mike. I'll get back to you.
Expert:  mike switzer replied 6 months ago.
if oyu have a moment i would appreciate if you could leave me a rating as this is how we are compensated from the site.

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