Battery Drains Dead in 24 hours


New member
2008 Envoy SLT.. 6 cyl. Parked the car after coming home from work and the next morning it was totally dead. No dome lights or dash lights. Once I put the key in the ignition I could not remove it.

Battery was a 2012 and I replaced it thinking a 7 year old battery was the issue and at first it didn't want to take a charge. All seemed well for the rest of the day.

Next morning I went out to the car and same issue. Battery was stone cold dead. Was able to charge the battery and get the vehicle started.
Decided to run a scan and had a P2431 code that pointed to the A.I.R. system.

I shut the car off and as I exited I heard a small motor running that was not audible from inside the car. Disconnecting the battery stopped the motor, reconnecting it and the motor was off. After about 5 min. I heard the motor start up again. I was not touching the car , was cleaning up. then the motor seemed to go through different speed modes, something it is not supposed to do.. I thought "Is this car possessed"?

Was the A.I.R. pump motor located under the car on the frame rail under the drivers seat. Further investigation suggested a bad relay (Located next to the motor on the rail) or an issue with the wiring or the computer. The relay is energized by a ground signal from the computer.
I replaced the relay ($40.00) and the problem seems to be resolved.

Will Keep you posted if it does not work.

24 Hours later Battery still charged, drove the car around a bit, No blower motor running when I shut the car off... No codes available.. Seems the relay fixed the issue.

Foot Note: QUESTION: The wiring is designed so the motor has power always energized. It is controlled by grounding the relay, a signal from the computer, Can anyone logically explain to me how the motor could run at variable speeds???... I can understand a relay being intermittent but not make a motor run at half speed.
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Off the top of my head, it could possibly be the BCM starting to go bad. One of the symptoms of this is battery drain down. However, if your relay replacement fixed that, count your blessings and keep going!