Hummer H2 Battery Drain
 

Good Day All.

I am looking for some advice regarding a 2003 Hummer H2.

I am having a problem with this hummer draining the battery over night.

I have done load test via the fuse board and it seems that the TBC is drawing around 4amps when not in use.

This seems to be very high, I am used to anything over 0.5amps being to high.

Also since this problem started the lights can now taken over 10 to 15min's to turn off, even after it seems that eveything has shut down there is still a battery drain somewhere.

Thanks for your time, and advise.

Best Regards.

RE: Hummer H2 Battery Drain
 

So everything is off and the load tester showed a 4 amp drain? If that is the case I would hook up the Load Tester again, then go to the fuse panel or box and pull out one fuse a time and then check the tester each time, put the fuse back in after you check it and do that until the tester showsno drain and that will give the area/source of the problem by seeing what fuse you pulled and the system it protects.

RE: Hummer H2 Battery Drain
 

Have you had any aftermarket electronics installed. DVD players, nav units, back up cameras, etc. Many dealers add these items at the dealership and they are not properly installed. I had the same issue with my 2003 H3. Took awhile to trace it down. It will start to show up more often as the battery gets older. You should be able to set the amount of time the lights stay on after you shut off the vehicle at your in dash control panel.

RE: Hummer H2 Battery Drain
 

we had a vehicle at the shop a couple of years ago that was killing the battery like yours. we had put a security system on recently and the dealership of course blamed it on us, so after a while, we traced it to a defective glove box light that began staying on. gunnyret is right-its a pita, but about the only way to be sure.

RE: Hummer H2 Battery Drain
 

I have had the battery on charge over night, reconnected battery, and then left the hummer alone for a good hour, then once I was sure that eveything had powered down I did current draw tests at the fuse board.

TBC 2C - 1.56A
TBC 2B - 0.00A
TBC 2A - 0.00A
FLash - 0.00A
AUX PWR2 - 0.00A

Can anyone tell me what the "TBC 2C" controls, and where it is in the hummer?

Thanks for your time.

Best Regards.

RE: Hummer H2 Battery Drain
 

I don't have my H2 or manual anymore but the Owner's manual should tell youwhat each part of the fuse board controls.

RE: Hummer H2 Battery Drain
 

Found out that the battery was apart of the problem, just was not keeping charge for long.

Still have a ramdon drain now and then, atm I have got a current meter on the battery and the hummer has shut down it is only drawing 0.30 - 0.35amps.

For the last week I have been able to get in the hummer and start with out any problems, but today the battery was flat again.

So I still have something drawing current when it feels like.

RE: Hummer H2 Battery Drain
 

If you haven't found the drain on your own I would take it in. A new battery will mitigate the problem for awhile but you will eventually kill the next battery also.

Has any one figured this issue out. My 2003 Hummer H2 has been draining the battery. But it only does it when its cold weather. Below about 45 degrees. Just thought I would check, no one has posted on this issue in awhile

still too much, i had .3 on a car . it would go a week or 2 depending on trips . then a short run and sit for a few hrs,,no crank. got to track it down bt pulling fuses.

fwiw,h3
 

off all nite.
connect amp meter, reads 2.5 a for apx 1 min,then .11 amp.
did it twice.
reconnect, 12.08v,start,14.8 apx 1 min then 15.33.
lites/fan on,14.8,then up to 15.3
that seems normal

2003 H2 Battery drain, found problem
 

Hey folks, I had a parasitic battery drain going in my H2, that was draining my battery overnight. Well I found the problem. My heater/AC motor blower was just barely running ALL the time, pulling 40 amps. Even with key off, the motor continued to run. ****You could not hear the blower motor running, because it was very very low, but draining the battery. I felt the blower, and could feel it running*** The blower motor resistor was bad. I was able to order the part through AutoZone for 220$, and its an easy fix.

Under the right side of dash, remove black plastic cover. Its held up by 2 7mm head screws. Directly under the glove box door is a black module about 3x4, with wires leading to blower motor (unplug at blower), and wires leading to the module (unplug from module). This is the blower motor resistor, and its held in by 2 8mm head screws. Unscrew them, and module pops out. Reverse process to install.

My power drain was driving me crazy. I hope this reply helps someone else having the same problem. GOOD LUCK!!

Warren Grant

Warren, just a quick thank you. A thank you for actually providing the solution to your problem so that others my benefit from this board. It's so aggravating that people don't do this on all the post. When you get answers like "search" or "refer to the manual" or "hey, I figured it oh", nobody gets help and it just makes for that much more junk to wade through. Good job.

Warren that is a good tip. Thanks! I will keep that in the back of my mind if I ever have a drain problem on my '06. I had an '03 that I fought an intermittent dead battery and it turned out to be the ignition switch. Even though the key was out the switch was still suppling power to things when it should have been off. The switch was only $30 something so I got lucky.

Hey how did you diag this problem to come up with your solution?

Warren how did you find out that it was the heater/AC motor blower was just barely running, how do you check for that, I want to check to see if its that same thing is draining my battery?
And Merry Christmas to you and all the Members on here