Battery is dead after SUV sits overnight

TONYNEAL

MEMBER
2002 GMC ENVOY
6 CYL
4WD
AUTOMATIC
270,000 MILES

If I hook up the battery charger, with the battery in the SUV, it will not charge. But
If I disconnect one of the battery cables
it will.
Now, the battery stays charged, and I have only head and brake lights, but lost all cabin and dash lights, windows, door locks, blower, stereo, and can't use the fob.
Any ideas?

1 Reply

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

This sounds like you have a definite parasitic draw situation going on here. Parasitic draw is the term we use when a component, for whatever reason, either not turning off, being left on, or a short to power somewhere in the electrical circuit, keeps that component powered when it shouldn't, and thus draining your vehicle's battery overnight. Here is a link below to a generic guide on parasitic draw for you to go to below:

https://www.2carpros.com/articles/car-battery-dead-overnight

In the diagrams down below I have included a guide on how to specifically track down the parasitic draw and isolate it to the offending circuit[s]. Please go through these guides and get back to us with what you find out, and we can go from there.

Thanks,
Alex
2CarPros

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