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Parasitic loss on battery!

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Hello all, 

I just picked up a 2003 Suburban 2500, 8.1 4x4 with 203k. It runs and drives great, except for a few issues-

1- tick/ knock in engine, don't know if it's lifter or piston slap or worse. Increases with RPM, but runs fine.

2- rear block leak. May be rear main, may be oil pan, I don't know yet.

3- parasitic battery drain killing batteries.

4- 4x4 works fine, Auto 4wd says "service 4wd system." 

5- had leveling blocks installed, says "service autoride system" or similar, don't remember the exact verbiage.


The problem today, is electrical. I put a new battery in it on sunday. Tried to start the truck today, Tuesday, and it's totally dead. Got it charged up and started and now I'm trying to find my loss. I have a clamp on ammeter on the positive cable, and with nothing on, it's bouncing from .15 to .25 amps drawing!!! No wonder it killed it. 


I started pulling fuses individually with no results, so I just got frustrated and pulled ALL the fuses, under the hood and out of the fuse box on the driver's side under the console. It has an aftermarket alarm, there are 2 extra 15 amp fuses under there and I pulled them, too. No difference. 


Are there any other fuse boxes or locations that could be drawing power? I'm at a loss.




Edited by Phoenix02
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Check the right side end of the dash, there might be some fuses there. Can you get a spec on the allowable parasitic load? The radio presets, the computer, maybe other computer(s) maybe the transmission controller if it has one. Get a GM reference for the location of all the grounds and ensure all grounds are clean and tight. Could be a always hot line is shorted someplace....

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