battery dies overnight

[Dana Brown]

My battery dies overnight. There seems to be something pulling from the power.Anyone ever seen this?

[Treeshark]

Yep, problem with mine was the rear tailgate window was trying to go up all night. Turned out that the key switch centering spring was broke, and after you had closed up the window with the key, it just kept on trying to go. The only way I found this out was because I had started the glass up one day and forgot something. After I centered the key, it kept on going. The switch is a b*tch to replace, so I just bypassed it and only go from inside now. Hope that switch doesn't go bad too! :D

[woodstock]

I would guess it is some sort of short. I have the same problem in my "pseudo" parts rig. I'm no electrical genius, maybe Joe will chime in here. Since mine is just about ready to be parted out I just disconnect the negative terminal so the battery doesn't drain. I also had a similar problem on my 88 GW; turned out to be in the tailgate also. The wires in the hinge area were pinched and the main one shorted the battery out. I probably should have done more to fix it, but I just taped them up and everything is cool now. Good luck!

[ December 20, 2003, 06:08 PM: Message edited by: Joshua Blossom ]

[carrotman]

I've heard about putting a volt/ohm meter between battery and positive cable, then pull out and replace each fuse until no power draw. That fuse will put you in the ballpark for what's drawing power.

[Joe Guilbeau]

To quickly troubleshoot a short, get access to an hand held multimeter. The meter should have an amperage capibility.

Normally these meters will have a 10 AMP current measuring capability, in DC voltage.

So, disconnect the Negative Battery cable from the Negative Battery Post.

Place the meter leads so that you are set to measure DC amps (current). Place the Red lead on the Negative Battery Cable and the Black lead on the Negative Battery Post. You will read a current, sonething on the order of 0.02 amps or so will be pretty normal. This represents the Digital or Analog Clock in the dash, some radios and stereos need a constant power source in order to keep the presets in memory and various other items that folks place in their vehicles.

I am not a mind reader, so I will address a retalively stock system.

Something around 20 Milliamps or 30 Milliamps wont discharge the battery overnight. Any current that is more substantial than this is going to cause the battery to discharge faster.

But what is causing the drain on the battery?

By simply removing fuses from the fuse block until (hopefully) the majority of the amp draw is removed, you have isolated the short to one circuit (that which the fuse protects).

In some cases, the alternators are to blame, and disconnecting them from the circuit will remove the current drain...if removing the alternator from the circuit (both plug and BAT cable) then leaky diodes are at fault and a new regulator is in called for.

This will narrow it down to the essential circuits on the Jeep...lighting, seats, power windows, etc...

Once you have it isolated to one circuit, it becomes much easier to troubleshoot.

[Sbonley]

One that I have run into more that once, if you have an underhood light with a mercury switch (It come on when you raise the hood), those have a bad habit of staying on because the switch goes bad and kill the battery.

[will e]

The Amp meter is a good trick. Be careful to avoid trying to start the car since this will try to draw a lot of amps through your meter.

First thing I would do is put the truck in a garage in the dark and see if there are ny lights on. In your case I doubt that is the problem since it drains overnight HOWEVER The terminals on my fog light switch were just barely touching and they drew enough power to drain the battery overnight. (Turned out the battery was bad too).