Something is draining my battery when the car is turned off and is usaully completely drained overnight. I have bought a brand new battery and it still drains the same.

What causes a battery to drain like this? I have had all the wires that were bolted on the back of the cylinder head ripped off for some unknown reason, I reattached the engine ground strap, and I have grounded the ECM to the intake manifold bolt. Was there anything else grounded to the back of the cylinder head that could be draining my battery somehow?

The intake bolt that the ECM is grounded on currently is the same bolt that the alternator brace arm is bolted to. Could this cause any drainage?

Also the rear hatch has stopped working, could this be any source of drainage?

I know this is a hard to solve problem, but does anyone have any ideas on what is draining my battery?

 

check the rear hatch pulldown, when these motors get jammed or otherwise broken they can continue pulling power even with the key off. there is a relay behind the rear hatch trim panel (down where the pulldown motor is), just disconnect that relay and see if the problem continues. you will have to recharge the battery after disconnecting the relay. try it for a couple of days and let us know.

 

standard test for battery drain is to hook an ammeter up in series with one of the battery terminals and see how much current is flowing with engine & all accessories turned off. should not be more than a small fraction of an amp. if current flow is more than it should be, leave ammeter hooked up and start pulling fuses from fuses panel one by one until current flow drops to where it should be. (don't forget to shut drivers door when pulling fuses, domelights draw around an amp by themselves)

ammeter doesn't need to be anything fancy, the $10 walmart variety will work fine for the job.

 

I second what 2vmodular says; you can also achieve the same result with a test light.

Remove the positive battery terminal. Hook one end of your light to the battery positive post, the other to the positive battery wire that you just disconnected. Now, the light will come on whenever there is something in the car trying to use power.

If you want, you can remove all your domelight bulbs so you can leave the door open all the time. Or pinch the doorpin with a pair of Vice Grips to get the light to go out. Or just shut the door every time; whatever you want to do.

Like 2v said, either remove the fuses one by one until your test light goes out........ or first remove ALL the fuses, then re-install them one by one. Once you've found the fuse that's your problem, start inspecting everything on that circuit.

I don't know a whole lot about those hatch pull-down motors, but GM sure would be stupid enough to make a design that would just keep running on and on when something has gone wrong.

Also, check the obvious. Make sure any lamps, like the center console and trunk, go out when you close their doors. Make sure the cigarette lighter is working properly, and pops out when it gets hot.

 

Do what the other guys said.

And also, if you have a hood light, dont forget to unlug it or pull the bulb. And your battery will die if the hatch pull down is messed up. The nylon gears inside are prone to breaking after a while. The gears in mine broke and caused my battery to die also. I didnt wait to see if the hatch closed, the next morning I was late for work. Kind of a pain to fix also. But thats another post.

 

The best way to find this type of problem is to disconnect one of the batt. leads and insert an ammeter in series. Then pull fuses from the fuse block one at a time. Normal standby current with key OFF should not exceed 1 amp. You will know by pulling fuses one at a time which circuit is at fault.