So I mentioned it briefly in another thread but I've been plagued by dead batteries for over a month now. After going through 3 alternators, I found one that seemed to work, and not to mention COUNTLESS batteries from Costco's blanket 100 month return policy (I Highly recommend buying them from them it's saved me well over a grand or even two in batteries).

So it was running flawlessly, started up great, batteries had a good charge after driving, and likewise the next day. Left it sitting there for two days, and they are drained COMPLETELY, not even a little bit of a charge left, 0 volts, nothing registering on a meter.

I can't deal with this crap anymore, I'm really thinking about selling this thing, and getting a CC w/ 351W (guy is asking 2.5K), or 5.4L Expedition (Asking 3.5k but he's motivated to sell), and just cleansing my palate of this truck, and buying another IDI down the road...
I need a truck that I walk out to and it starts up first time when I need it too, and I can rely on.

My uncle is calling his buddy that deals in the electrical systems of these older trucks, cause it's clearly over my head.

Heh, unless there is someone in BC that wants a truck with a Solid rebuilt 7.3 with 170k on it. *cough* minor electrical issues *cough*

 

Some sort of parasitic drain? Something has to be drawing current all the time if it keeps killing your batteries. Have you checked the voltage regulator too?
I want to say if you disconnect the grounds (both batteries) then put a volt meter from the ground cable to the negative terminal, it should read zero while the truck is off. If its reading anything else, there is power flowing through a circuit somewhere. Start pulling fuses until it stops, then you've found the circuit to check through.

I might be wrong on this, can't quite remember. Also, the radio will pull amount of current to keep the clock running, so pull that fuse first.

 

something is staying on.

its been a while but someone will correct me. take the positive terminal off and reconnect the circuit using your multimeter. you shouldnt show voltage.

whoops. you cant delete posts here?

 

The only thing not replaced has been the regulator, mostly because up until a week ago I didn't know what it was, but the truck was working flawlessly so I didn't worry myself with replacing it, but after sitting there two days. Dead batteries.
Also the radio was replaced with an after market one, which doesn't have a clock in it, the only thing it does is store station pre-sets.
I'm gonna go hit up a couple pawn shops to see if I can find a battery charger for a fair price, and then reconnect my battery disconnects.

 

Well picked up a Motorcraft 75/12/2 charger from the shop for cheap, and I've got my first battery charging, seems to be doing pretty good. I was tempted to buy 2, just to charge them both at the same time.

 

This may sound stupid but this was my problem,
do you have a backup camera for hooking up trailers and stuff,or light bars that go under tailgate? when i installed mine i didnt put a switch to turn it on or off i just wired it straight to my battery ,was pulling my hair out trying to figue out what was wrong !

 

Under hood light, glove box light etc......

 

No backup camera, no light bars, my under hood light has never worked, I think it's burnt out, or missing, and as best I can tell the glove box light turns off when it's closed, the press button cuts it out good.
I have a Warn enforcer bumper, but the lights on it are rigged to cab switch, that I checked and it was in the off position.

 

I use a test light instead of a multimeter so I can see when it goes out when I pull fuses. Another idea. Start unhooking things. You will find it.

 

these trucks once started can be powered with a 9 volt battery. then engine is solid, if you do sell it, as just the engine, you dont need to worry about mentioning that part. you have a gounding short that is killing your batts. seems that the drain is pretty bad too. i found mine by taking a multimeter to the frame and chassis, i found a naked wire rubbing the body, it was delivering nearly 4 volts to the body but never popped a fuse....go figure that one out! lol

 

I had a bad starter act that way. If I drove the truck every day it was fine. Let it sit 3 days and the batteries were dead.

 

if ur going threw batterys do u repalce them at the same time and are they the same size one bad battery could drian the good one

 

I had the same issue and it ended up being one bad battery draining itself and the good one with it. Replace both at the same time?

 

Replacing them in pairs.

 

You could also disconnect one battery at a time to test them individually. I've had batteries randomly go from charged to dead as a doornail in a matter of 20 minutes.