First off, hi everybody: ) I have a 2001 Dodge 2500 Maxi van, 318, with 118,000 Miles. I bought it used about 3 and 1/2 years ago, it had about 90,000 miles then. About 5 months ago, the battery went dead for no apparent reason. CAme out one morning, would not start. Even tho the previous owner had replaced the battery, I got a HD Napa battery. All was good for a while, and then, then, one morning, the battery was stone dead again. I noticed that I had left the wipers on, and figured that there was a short in the switch. So, I started making sure that the wipers were off. Seemed to be ok for a while, then, the battery went dead again. I charged the battery on my charger, and it would not hold a charge.I took the battery back to Napa, the battery was stone dead. Verdict; defective battery. Put the new Napa battery in, all was good for a while, then, dead again. I did the old school test of pulling the battery cable off, while it was running, it kept running. So, the alternator is good, right? There seems to be no pattern to this, it will stay good for weeks and weeks, starting every morning, then, one morning, its dead. It seems to happen when something is left " on", like the ac switch, and/or the wipers. But, not always. In otherwords, I can forget to turn the wipers off, and of course they stop when the van is shut off. And will not always " drain" the battery. But sometimes it seems that they do. It seems to happen only when its been sitting for 12 hours and /or days at a time. What is happening here? Where should I begin to look? I have added nothing to the van that was not there originally. Where is the most likely place to begin to look for this short? And what might I need to repair it. I'm an old school sort of mechanic, that means that I can do valve jobs and clutch jobs, but am basically lost with the modern vehical's electrical system. But I generally can get thru most anything, sometimes needing some help from you guys that are doing this for a living like I used to way back when. Please help! Thanks!
Okay get a voltmeter and read the battery open voltage before you start it-record it, it should be between 12.4 and 12.8 volts-now start it up and put headlights and heater on high. The readings should be at 13.5 to 15.5 volts volts while engine is running and loaded.
If you got the open and running voltages. Now disconnect either of the battery cables stick the meter leads from the battery post to the disconnected cable do you have a reading, if so start removing fuses one at a time, the one that turns the light off is the trouble area-it has a direct short to ground.
In the event there's no excessive drainage or case drain-start troubleshooting between the alternator and computer- The computer controls the field generation.
See EWD below
October, 24, 2007 AT 9:07 AM
Hi there, thanks for the info, now I have a good starting place: ) I'm going to try and get a bigger pic of the wiring diagram, right now I can't read the text on the page that you posted. Thanks again, Art