I have resorted to pulling the wiring harness connector at the battery every night because I haven't been able to find the leak yet. The only thing left it to pull the alternator wire. I pulled one fuze at a time with no luck. Everything else (electrically speaking) seems to be working fine. The alternator charges fine, the battery hold charge perfectly all weekend as long as the harness is unplugged. Just another annoyance right now...

 

Heres how I would do it. Set voltmeter to read 12 volts. Disconnect the positive Battery cable. With the switch off connect the voltmeter - lead to the + battery terminal and the + voltmeter lead to the + battery clamp. The reading you get is the draw. If you don't have an alarm system the reading should be 0 volts (yours won't be since you have a battery discharge problem). Reconnect the battery. Now go to the fuse block and remove one fuse at a time. Place one lead on each side of the fuse holder and take a reading of current draw. It should be 0 volts (maybe a slight reading on the radio for the memory). Wherever you get a reading, thats the offending circuit. Don't forget to check any circuit breakers at the fuse box. Test them the same way you test the fuses. A big culprit is the electric door locks. They will either short out or partially stick causing a battery to drain overnight. If all the fused circuits check good then do the same thing with the wiring to the charging system. any place you can break the circuit , you can check for current draw. Follow the power distribution chart in the wiring diagram to make it simple. Good Luck.

 

Thank you mister Searcher; I am going to put this thread in my "subscribed threads" for future reference.

Oh, by the way, when you said "with the switch off", were you referring to the ignition-switch or the switch on the volt-meter ??

Thanks.

 

The ignition switch, just like you would park it overnight. Just be careful working around a battery that still has the neg. cable attached. A dropped tool can ruin your day. I found this problem with the wifes van and door switches that constantly got abused by my knee getting on them as I drove it. My knee would push it partly and it failed to return to center and would try to lock the door all night untill the battery died.

 

For draws, I like to put an ammeter in series with the battery. If we know how many milliamps the draw is, we'll have a better idea of what we're dealing with.

30 milliamps is the maximum rule of thumb for allowable draws, after everything times out. If it's over 200mA, it's a pretty big draw.

 

I agree with using the ammeter. My problem is that mine only goes to 10 amps and a bad short (sometimes I like to jiggle wires and switches while connected to the battery or fuse holders) would burn my meter up so I never try it, but it is the best way.

 

Thanks for the detailed info Searcher. I too will be able to use this information in the future.

 

I know this is probably obvious , but if you have a "under the hood worklight", remove the bulb before you start testing for the draw as searcher described..... and if you are going to leave the door open, disconnect or hold back the dome light switches....

 

And when you have time, install master over-ride switches on both lights, in order to kill them when the hood, or doors, will be open for a long time; this comes in handy more often than one would think.

 

No hood light... good advice though. I will be hitting it hard over Christmas.

 

I did buy a master disconnect switch to kill all the power! It's the kind the pullers have to use on the back of their rigs for emergency shutoff...

 

I had same problem.

This too is an obvious suggestion. When you take the key out, make sure your not taking it out in the accessory position.

On my 98 1/2 the key slides right out in the accessory position. No stop or catch, like every other vehicle I've had.

The drain can be quite substantial even if you don't have any accessories running, it would drain both my batteries in about 4 days.

 

the alternator going out can cause a short and if you remove the large charge wire and it wouldn't hurt to remove all leads to the alt. and test of amp draw at battery. Just one that caused me a problem in the past. ED

 

And a BIG FIRE.

A lot of vehicles have burned to the ground, along with the buildings they were parked in, on account of alternators shorting internally; no one has to be around for it to happen, either.

 

I have three test meters but have found that a little dash light bulb with a couple of wires soldered is really handy. My truck was killing it's battery every couple of days and I found out where the problem was using one of these bulbs. I have not fixed it yet, I just left the fuse out for that circuit. Just about any small current leak will make the bulb glow. I started with the battery and worked in.