lochiiel

My 2002 Suburban 2500 loses power in the battery when the vehicle is parked for an extended period of time. The battery is less than 1 year old and the charging system working fine so it appears something is drawing a small amount of current when not running. The Onstar system seems to work without the ignition key being on so I'm wondering if this could be culprit? As I understand it my Onstar system is no longer functional but may be drawing current in an attempt to establish a connection. If this is the problem can it be permanently disabled?

Thanks.

in2pro

Welcome to the forum..

That is possible , but I would also consider other sources such as under hood lamp not turning off, vanity mirror lamps and any and all accessory power outlets...
Do you leave any items like phone chargers or GPS units plugged in...
I am not sure which fuse is used for the On Star but it might be worth pulling a few fuses at a time to help isolate the offender...

kevinkpk

Few ?'s is it only after two weeks, or one week, any other time frames or do you know? I know you said the battery is less than one year old, is it possible to unhook the ground cable from the battery once you park it? This prove either the battery or something else causing the low battery. Does it jump start easliy? What part of the country?

MDTAHOE

What brand is the battery? How many mA are being pulled on the battery after everything time out?

lochiiel

Thanks for all the quick responses. The battery is OEM dealer installed about 1 year ago and I first noticed the problem not long after--the vehicle is new to me so I don't have much history other than it is in excellent condition and has been regularly serviced by a Chevy dealer.

I use this vehicle primarily for longer trips so it is not uncommon for it not to be used for a month or more and that is when the battery gets run down. I have other vehicles that don't get used for several months at at a time and have never experienced the battery running down as in this case. I always remove the ignition key when not in use so I presume all systems would be off. I haven't noticed any accessory lights being on.

When I jump start it the battery charges quickly and there are no issues with it unless it sits for an extended period.

I'm wondering if the Onstar, or something else, puts a load on the battery when not in use? If I can just pull a fuse to disable the Onstar that would seem to be the best answer.

kevinkpk

New dosen't mean anything. You could have a weak cell dragging the others down with it til the voltage is too low to start.
What I had suggested would prove the battery or indicate the battery, or buy a $5 hydrometer and check the cells if it isn't a sealed battery. If the battery is good, I'd suggest pull fuse on radio, let set, if that isn't it, it will be a process of elemination.

MDTAHOE

All modern day automotive batteries are considered sealed. Just because one car holds a charge for months does not mean another will. It has do with the reserve capacity of the battery and how many computers and accessories a vehicle has. A rubber floor no power anything work truck will stay charged much longer than a fully loaded Escalade. When it dies is it being fully recharge by a charger? I would recommend keeping it on a battery maintainer and you will not have to worry it anymore.

bdburb

Our neighbor bought a 2003 GMC Sierra brand new. He has had the same problem since day 1. He took it into the dealer countless times for it and they told him there's nothing wrong with it and it's normal for all the electronics in the vehicles. They suggested installing a low voltage disconnect or a battery tender. I highly disaggree with their solutions... He put a low voltage disconnect in.

in2pro

Seems like I read somewhere that after about 3 days the OnStar module goes to sleep...I agree a battery minder would be a good choice. Auto batteries are not designed for repeated extended times of discharge...