First 5.3; battery dies overnight

[cletus van damme]

Just picked up a 2001 Suburban with 200k on it. Runs great, but battery keeps dying overnight. Any usual culprits with these body styles?

I just recharged it and am gonna reinstall but disconnect the alternator to see if that is killing it.

Any other ideas?

thanks

[dsraven]

remove and clean up all the cable terminals and ground points including the starter end and block ground. check to ensure that any corrosion hasn't worked it's way down the battery cables. sometimes you have to cut the big lump of insulation on a side mount terminal to get the terminal clean and free of corrosion. load test the battery after a full charge. if good check for a draw from the alternator. if good put a volt guage between the battery cable and the battery(with the cable off the post) and start pulling fuses while watching the volt meter. if you have a draw you will see the battery voltage. when the draw stops, or drops the voltage, you have found the problem circuit. the radio will have a draw for memory. don't forget to pull the interior light fuse first because it becomes a draw as soon as the door is open. it'll fool ya. don't forget to check the trailer hitch plug and related connections. especially if you have the rv style plug. the back side can be full of green corrosion and short out the trailer battery charge wire.

[pamoffa]

If you have a volt meter check the bat voltage with the truck off should be around 12v turn the truck on and it should go up to 13 or more this will tell you the alternator is working. I would check for any lights not going off when you turn the truck off. I'm not sure what lights your truck has but there can be under the hood lights back area light visor lights a week battery could be killed by this.

[91short]

Gauge cluster could have a short in it. Find out which fuse if for the gauges and pull it, see if it still dies. My father had to have his replaced.