Ok, so I've been having some problems with my 93 Dakota with the 3.9. My volt meter will work sometimes (usually when I first start the truck for the day). It will continue to work until I shut the truck off, then it won't work for the rest of the day. And might not work for days after that. I've been leaning towards my other problems with the truck being computer related, and I've read that the voltage regulator is in the ECM. Can anyone confirm this, or give me some advice... Thanks

 

g. man

I don't know if this is related, but I'd check the 3-1 wire splice in the wirng harness behind the relay box on the drivers side under the hood. If this splice is going bad you'll have trouble in the future and it's a good thing to get fixed before you have troubles....like a no start.... I just fixed on on a 95 3.9. That thing was totally gone! The tape on the harness was blistered up where the splice was.

 

..I know the VR is in the ECM on my 91 5.2, not sure about others, but I had similar problems...it wasn't just that the volt meter was erratic, it was correct, it was the charging system that was not working correctly...new ECM fixed it.
...also on my truck, the PO had a shade tree mechanic who had bypassed the VR function of the ECM by installing an aftermarket VR on the firewall and jerry-rigging it to the alternator, and every one of his splices and connections were loose...

 

Thanks for the reply's. Yeah, I've been meaning to check out the notorious splice under the power distribution box, but haven't got to it. Another thing I noticed though, was that my ECM has yellow markings on it, like you see on salvage yard parts. So I think maybe the computer has been replaced, and maybe it's not quite correct for my exact truck. I read somewhere on here that you can have your computer flashed to your VIN number? I've been wondering where you would have this done. You can buy them ready to go (flashed to your VIN #) for 200 bucks on the net, but I want to have mine checked out before I spend the money. If any one knows anything about this, or where you can have this done, please post Thanks

 

1- Can anyone tell me how the volt-meter works?
2- Where is the voltage regulator? Is it in the ECM?
3- How can I fix mine?

 

The voltage regulator is built into the PCM and is non-serviceable. The VR is used to control the voltage from the alternator. The VR has nothing to do with the volt meter. There is a way to test your volt meter. The service manual has the procedure. You can download the service manual in the FAQ in this section a few posts above this one. It has EVERYTHING you will ever need to know to diagnose and fix the truck.

 

There is '95, and '96 available in the faq, but not '93. I have the Chilton, but it doesn't say anything.

 

95 is the same 92-95

 

unless were talking fuel filters LOL

 

So really there is no reason for this forum then. Anyone with a technical question can just be refered to the FAQ, and download a manual. Hmmm