Parasitic drain

JJBLUR

MEMBER
2005 CHEVROLET TAHOE
5.3L
V8
2WD
AUTOMATIC
140,000 MILES

The battery drains flat after two days of sitting. Has new battery, starter, and alternator. With a meter reading amps between negative post and cable it gets down to only.620 ma. Only the rear A/C fuse has much affect when pulled. It drops about 25 ma. Everything else drops a few ma here or there. I even pulled every fuse under the hood and under dash and it still read.620. It was not until I pulled the 40 amp ignition A fuse the ma went to.035 with or without all the other fuses. I cannot find any shorts anywhere. No lights anywhere left on. Remote start power has been disconnected which showed no real drop. Could a faulty ignition or them ECM need to be re-flashed because of not putting stuff to sleep? Thanks My car has 150,000 miles.

1 Reply

KEN L

MASTER CERTIFIED MECHANIC
48,363 POSTS

Hello,

These are always fun. I am thinking if you have a CD player one of the CD's is stuck which in not let the radio rest which is powered by the BCM and the ignition circuit. Next check the seat switches to see if one is stuck in a position.

Here is a guide that might help as well.

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

If all else fails it could be the ECM but I have not seen that problem before.

Please run some tests and get back to us so we can continue helping you.

Cheers, Ken