Money Pit

[sandienleon]

I have a 1999 Jeep Grand Cherokee Laredo and the batery will not hold a charge. I have replaced the alternator and battery and after three weeks the battery is dead. I have been told that the On Board Computer is malfunctioning and is causing lights to turn on at night and drain the battery. Has anyone heard of this issue? Thanks.

 

[EarthCruzn]

You say you installed a "NEW" battery and alternator and it takes 3 weeks to drain the battery........ are you driving the jeep at all during the 3 weeks? Do you have any devices installed aftermarket ie.. radar det, cell charger, CB, Aftermarket stereo anything like that, or fog/drive lights. Basicly any thing that is not stock?

 

[82CJ7JEEP]

Look in the other forums, there was a thread a week or two ago that was similar. It was not in the CJ forum but the one below it. Alot of good information.

 

[54cj3b]

I have a 88 that does that to I found its sometimes the rear hatch not closing all the way even though it looks like it same thing with the rear doors could just also be a bad ground issue causing you issues
few things to look at

 

[JPNinPA]

good batteries just don't go bad. If you know how to use a multi meter, set it up to monitor the current from the battery with the engine off. It should be like 10 mA or so. If its higher you could start pulling fuses to determine what is drawing the current. From there you could check what is hooked up to the circuit. I'd start with the above suggested items. Anything aftermarket or any circuit you altered. I've seen some hook up 1000W amps off the battery without ignition switched inputs. This is a constant high draw in some cases.

 

[mattduran]

Multi meter is a good idea. Something is definitely off there. Another easy quick check is to take the key out of your ignition and remove the positive post and touch it back on the pos and see if you get a spark. If your getting one that something is drawing is still drawing current.
You should remove the positive post off the battery every time your not using it. A pain but would save some trouble until you figure this out. Good luck.

 

[tjlboise]

Multi meter is a good idea. Something is definitely off there. Another easy quick check is to take the key out of your ignition and remove the positive post and touch it back on the pos and see if you get a spark. If your getting one that something is drawing is still drawing current.
You should remove the positive post off the battery every time your not using it. A pain but would save some trouble until you figure this out. Good luck.

The spark thing you're talking about is a good and easy preliminary test to see if that's what's going on. I don't know about this computer brain causing the battery to drain. Its possible, but it doesn't sound likely to me. Like a few others said, its most likely some after market mod that was installed incorrectly. Electric problems are usually a pretty simple fix, but it can be quite a hassle narrowing it down to finding out what it is that's causing the problem. Luckily you're on Jeepz and you have lots of good folks to help you out. Good luck. Let us know what you find out.

 

[dustin g]

I had a similar prob a couple years ago. It was my passenger side door switch for the dome lights. The switch went bad and would only temporarily register then turn the lights all night. Took forever to find.

 

[frhrwa]

definitely a draw in the circuit somewhere.. the meter is the best answer.. find the component and take care of it.. removing a fuse at a time should point you there, like said above.. and if you do leave you vehicle for periods of time, even without the bad component, a battery disconnect switch might be a good investment..