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?

 

A bad ground would not cause this. This is called a parastic loss. That is when there is too much current being drained from the battery with the key in the off position. They are a real bitch to find. It could be a grounded wire, a bad switch, or even a stereo wired wrong that stays on all of the time. You will need an ammeter and know how to use it. With the key off, or not even in it, remove the negative cable and connect one probe from the terminal clamp and the other to the negative terminal with a test light. NOTE: make sure everything is off, no lights (doors closed, disconnect underhood light, ect). If the light is dim or off, it is safe to hook up an ammeter in the same manner. The ammeter should read around .030 of an amp (although some gm's drain as much as .060). If it's much more than that you will need to find the circuit that is drawing the current. To do this, pull a fuse to see if it brought it around the spec, if not, replace fuse and try another until all circuits are tested or the faulty one is found. Note: the computer power circuit should be tested last because that and the circuit the radio is on draws the most current normally. Then consult a diagram of the circuit and trouble shoot from there.

 

thats what mine was/is.

There is a thing called a short finder that will find magnetic fields in wires that should have none (no power). But, I just got a battery disconnect switch for mine.

 

If your rear hatch quit working that's where I'd start. Sometimes the electric motor will short out or never stop running, naturally draining the battery. If you don't have a multimeter pop the cover off and see if the motor is hot, if it is then that's your problem. If you do have a multimeter then do like the guy above said. Later