1999 grand caravan, weird electrical issues

can anyone help my moms 99 grand caravan one day started having electrical problems. first the dome lights stopped coming on when door was open, then we were outside and suddenly her headlights started coming on and switching to high beams then to low beams with no key in the ignition had to pull battery to stop it. then when running the engined died without warning and the number 13 relay in the drivers side fuse panel started clicking rapidly then stop flollowed by the door open chime. then the door open chime would stop and the relay would start rapidly clicking again. can't find out what the #13 fuse goes to. Mechanic said there was a power drain somewhere and another said he had heard this before and said it was the main computer that tends to go out in the 99`s any truth to this,any help would be appreciated.

Pull the head light switch and unpug it , hook battry up see if problem is gone , probly just a bad switch

All symptoms of low voltage. Make sure battery connections are tight and shinny clean. Have the battery load tested. Check battery cable voltage drop. Computers "go out" in any and every model year. The power drain could be the root problem.

While computers "go out" on any make and model of any vehicle that has a computer, some like the 96-00 caravan 3.3/3.8 have known pcm issues for various reasons that some of which are corrected by a flash reprogram with updated p/n depending on the symptoms. If you havent had any slow starting issues or had to jump the vehicle it is unlikely that there is a simple voltage drop issue although a voltage issue could definately cause similar symptoms. But with no other engine starting issues accomanied by these underlying issues there is likely a computer going into theft mode causing lights to flash low/high toggling and interiors flashing.. make sure alternator is not overcharging.. They have been known to have voltage regulator issues that have caused overcharging that has led to shorts in instrument cluster and damaged pcm's.. if obvious problems like battery and connections check out ok and problem persists disconnect the battery and un plug the pcm for an hour. This will de energize the pcm and all short term information will be lost including recent faults.. pcm is located on the drivers side near fuse box.. has 3 rectangle shape connectors with red lock tabs.. not a guarenteed fix but has worked in a pinch without spending money on otherwise expensive repairs.. good luck!!

My 2002 Grand Caravan had many strange glitches/electrical gremlins when I got it as it was left sitting with a weak battery. THey would jumpstart it and the transmission would kick into limp mode and various lights would do strange things. I would check for a weak battery as well, then go from there. Pay to have it properly fixed so it doesn't leave you stranded unless you can figure it out. I've had my van for 6 months and just under 8K miles and not had one issue since I cleaned the battery terminals and charged it up properly.