Thread: parasitic battery drain

New to form. Thanks in advance for the help. 2008 Grand Prix

No battery problems up to this point. three years into a 5 year warrantied battery. Car sat for 8 days while on vacation. Returned to a dead battery. Charged it up for 48 hours, battery now over 12 volts, car started fine. Using youtube I found the process of looking for a parasitic load with my multi meter.

I have a parasitic load on the battery of about 1.5 amps. I removed and replaced all of the small fuses (under hood and in car) but did not see the amp decrease. when I remove the under hood #26 40 amp fuse marked "BATT MAIN 1" the load drops to .18 amps. When I reinsert the fuse it goes up to about 3 amps, then slowly drops back to 1.5. https://youtu.be/XPQ01DKC3tQ
(Edit: When I disconnect and reconnect the multi meter I get the same increase to 3 amps and then reduction to 1.5...)


1. I do not have a wiring diagram. Does this 40 amp fuse feed other fuses that I may have missed the load drop?

2. If it is a problem on this circuit, any Ideas what to do?

try testing the in car fuse box.

you got a aftermarket radio by chance? maybe its hooked up wrong. and you could also get your battery load tested, see if its up to snuff.

#2. You will have to trace out circuit and find the draw, probably a short somewhere. Not a fun task.

But you already identified the circuit which has the problem, what does fuse #26 feed? The GM repairs manual with wiring diagrams would be helpful as it identifies the connector and location where the wires travel to, allowing you to trace each portion of the circuit if need be. This of course would only be necessary if the connected components to that circuit all check out. So... You know what circuit is a problem, all devices or components need to be checked first, then wiring...

good luck!

Unplug the alternator connections and retest they have been known to drain the battery if the regulator is schmegged

Originally Posted by Turbocharged400sbc

Unplug the alternator connections and retest they have been known to drain the battery if the regulator is schmegged

Niceeeeee... Hahaha learn something new every day (me) : )