First some background. 12v conversion, brand new battery, fresh install of new EZ Wiring harness, new alternator.
So I finished my wiring harnes job a few months ago, truck was fine since, ran good and everything worked. About a week ago my battery was dead and would not take a charge, so I got a new battery. Put the new battery in, truck fired right up and ran great. Next day, the truck won't start and battery reads less than 2 volts. My cheap $20 charger wouldn't charge it, so I connected the battery to the wife's Durango's battery with it running for a few minutes and that charged it up. Put the battery back in the truck and it starts up and runs fine.
What could cause a brand new fully charged battery to go from 12.5v to less than 2 volts overnight? I double checked and I did not leave the headlights or anything on. Besides, even if I had left the lights on, I don't think it would drain the battery completely like that. The truck was off and the key wasn't in the ignition.
So, I checked with an Ohm meter, and nothing is pulling any current except for the guages. When the truck is off and the key is out, there is a small amount of resistance in the Ohm meter.
I did this test by connecting a an ohm meter across the battery, which showed a little resistance, like 100 Ohms or so. Then I removed each fuse until it showed an open circuit.
So then I noticed, which I never noticed before, is that with the truck off and the key out, the gauges still show a reading. Not the lights, but the gauges themselves. The needle still reads the temp, voltage and fuel level. That seems starnge to me, I don't think it's supposed to be that way.
So first, are the gauges supposed to still get power even when the ignition is off? (They're brand new VDO electric gauges).
And second, could the gauges being on overnight be the reason for the battery to drain down to 1 volt?
Thanks!
Last edited by stevebolt; 10/15/2011 8:01 PM.
