Battery keeps dying

cattledogg · October 13, 2006

Ok, I am having a heck of a time with my battery dying after a day or two sitting. I have a 2000 suburban K2500 with 6.0 motor and 93000 miles. After it sits for a couple of days the battery will be dead and wont start with out a jump. I have found that I have about a 1.1amp draw which is way way high I know. Now if I pull the radio fuse it drops to.25ma draw, put the fuse back, while still having the meter hooked up, the amps go back up, but then drop down again after a few seconds. Now if I unhook the meter and rehook it back up the amps will be high again and wont drop unless the fuse is pulled like before. I have all the radio plugs and amp plugs unplugged and it made no differrence. I found that the radio fuse also has the insturment cluster and HVAC module in the same curcuit, could one of them be the culprit? Any idea on what I should do next or any idea what the problem may be. By the way the battery is brand new too. Thanks

GM-Tech · October 13, 2006

Are you allowing time for the modules to go into sleep mode before taking a final measurement of amperage draw? It could take up to 20 minutes for this to happen, so hook up your meter and walk away for 20 minutes.

When you pull the fuse and then stick it back in, you're waking up everything that talks on the data buss and now you have to wait for them to go back into sleep mode.

Its possible for any module to cause this kind of a problem, but I can't say I recall anything other than a BCM being a problem. Unlkely, but yeah, it could be an IPC or HVAC module. Usually, something aftermarket is tied into a BCM circuit that keeps it from going to sleep.

I assume that you've looked through the vehicle to make sure nothing is on when it shouldn't be? I've been bitten more than once by the lights in a visor vanity mirror being on all the time due to a faulty switch in the lid. Even with a completely dark environment, you'll not going to see that light with the lid closed and the visor up against the headliner, so it's easy to overlook.

cattledogg · October 13, 2006

No I hadnt waited that long, I will give that a try this morning and see if anything happens. I have checked ever light that I could find more then once and they all seem to be off, but I will check again. I do have an aftermarket radio, but if its all disconnected shouldnt that eliminate that? I will update later on what I find today. Thanks

cattledogg · October 13, 2006

Well this is all I could find out today, actually this is as far as i got when I dropped my meter and broke it. Hooked up the meter with everthing unplugged, all radio connectionc, amp, HVAC, and even the climate control fan over the driver seat(since it started making nosie the other day). The meter read about .85 to .92 amps. I then let is sit for a few minutes and once the security light on the dash quit flashing the meter readings went down to .25 and didnt move. So I started plugging things back in, got everything plugged in and it was still reading .25amps. And about that time is when the Fluke hit the gound and I was done for the day.

Yukon04 · October 13, 2006

0.25 amps is still pretty high. The entire vehicle while all the modules are "sleeping" should only draw about 25mA = 0.025A. A 1/4A draw will drain a used battery pretty quick. Keep pulling fuses until that .25A goes away...

.25A is about the draw of a small light bulb...