ZJMAX

So I have a 2000 JGC 4.0L auto 2wd. So here is the issue I am having. If I close the doors and let it sit over night the battery will be completely dead in the morning. Locking or leaving it unlocked does not matter still stone cold dead. Here is the kicker, if I lock it with the key fob the battery will be fine in the morning or even 4 days later still starts right up. Any ideas where to look for the draw? No interior lights stay on or anything I can visually see that would cause it.

Thanks,
Max

ixanay_on-the_exjay

Bleepinjeep has a video he did to find a parasitic draw he had on his ZJ. Probably the fastest way unless someone pops up on here and tells you exactly what it is. Unlikely...

dave1123

Seeing as how you're talking about a WJ, I might have an idea. When you just turn it off and close the door, the Body Control Module is still active. If you lock it with the key fob, the BCM knows you're not coming back and goes to sleep. If the BCM is still active, the PCM might also still be active waiting for the next start. Try this. Lock all the doors with the lock button on the driver's door console. Then get out and lock the driver's door manually by moving the slide on the door and close the door. You should hear the door locks cycle again and the alarm will be set. Once the alarm is set, the BCM should go to sleep. The system is designed so this won't happen if the keys are still in the ignition so you can't lock yourself out.

What is actually causing the drain? I don't know. The BCM is supposed to time out and go to sleep after a period of time so this won't happen.