dead short somewhere
 

There is a spark when you connect the cables. I don't have much in the line of testing equipment... just a test light. I will go disconnect the voltage guage and let you know what happens. thanks.

If its the volt gauge it should spark..........no spark then the problem is somewhere else

dead short somewhere
 

Sorry if this sounds stupid.... but do you mean when I unhook the voltage guage, IT will spark?

Normally it will not spark, if it does its likely the problem

Just thought of the cigarette lighters, have had a couple that caused a draw over the years

I doubt it's the gauge. a bad gauge would give a false reading but not drain all the batteries down. you have something drawing juice big time. there have been more than one ocassion where i left my 2 dock lights on over night for 14 hours & my truck started as if I left nothing on. no noticeable affect on starting at all. if you take the pos cable from the starter & touch it to the first battery & get a good spark, then something is pulling juice. one thing to consider... since it's draining with the truck off you can eliminate a lot of guess work.

it has to be something that could draw with truck off. it's not going to be anything that requires the ignition switch on. example... it is not going to be the heater, a/c, radio, whatever turns off with the key is not it. it is something that can function with the key off, like headlights, cig lighter, dome lights, e.t.c or the wiring going to or from them is where you will most likely find the short. the starter or alternator, would i.m.o not be it either cause they have no function when truck is off. a wire going to or from, could be the prob, cause they branch off & go to differernt areas. but not the alt or starter in & of itself. have you checked the 2 pos wires going from the alt to the regulator ? your prob is a hot wire somehwere. i.m.o.. I really wish I could be of more help. :sad:

is the truck hooked up to a trailer ? like i said earlier.. it is something that can be operated while ignition off & traler lights & the pig tail connection can get power with key off. if it's just the truck than you have less to go over.

dead short somewhere
 

Is both sides of the amp guage supposed to be hot with the key off?

on my truck I have a volt gauge & when i turn key off gauge goes dead. ( all the way to the left) when i turn key on it jumps back up. i have an intl, so my gauge will be diiferent. ign turns on a lot of accessories & should also turn off all those accessories when it is turned off.

An Amp guage will be hot on both sides, a volt guage has a Pos & a Neg. You could try unhooking the wires from the amp guage & see if it sparks, that would indicate a draw.