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?

Friday, December 13th, 2019 AT 11:55 AM

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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