Gmc Sierra Hd 2500 Battery Problem

taboss · March 5, 2009

I purchased a new 2008 Sierra HD 2500 pickup last fall. It now has about 7,000 miles. I have noticed that when left sitting for a week or more, the battery charge seems to drop. If I drive it every day (which I don't usually do), the battery charge is fine. About a month ago, after it had been sitting for approximately two weeks), the voltage on the batteries was very low and wouldn't crank the engine. I called GM Customer service and had it hauled to our local GM service center (Findlay Motors in Bullhead City, AZ). They replaced both batteries and said they couldn't find anything wrong. I picked it up and drove it a couple of days, then let it sit for another two weeks. When I got in to start it, the batteries were completely dead, no dash lights or anything would come on. I again had it hauled to our local service center. They charged the batteries this time and checked it out, but found nothing. They said it was drawing 7 milliamps of power when turned off, which they said was normal. I don't have any auxillary items plugged into the outlets, but the battery charge continues to deplete over time. I have a 2003 GMC Denali and have never had a problem with it's batteries (and it has set for a couple of weeks without starting too). Can you provide me with what I can do to resolve this issue?

pwall · March 5, 2009

Welcome to

Can't really offer any advice on what to check, but there is definitely something wrong. Initially I would have said the battery is crap, but since you mentioned GM already put two new batteries in, doubt the battery is an issue.

Hopefully finding what is draining the batteries won't be too difficult.

For what it's worth, my '07 (dual batteries as well) has sat for sometimes 2-3 weeks. And it's started with no issues every time.

Good luck....hopefully the root cause is found soon.

markw8 · March 6, 2009

Not sure about about a D-max. But if its a gasser it should not even be possible to drain both batteries with the key off. They are isolated from each other with the key off.

Mark