Hey all,

I just bought a 2000 Ram 1500 5.9 4x4. Just like my old one.

Here's the backstory. I got this baby for cheap because of the following:

Guy was driving it to meet at the test drive before I bought it. As he was driving, Check Guages light came on and voltimeter dropped all the way down. His battery was fried. I used my truck to jump it and drove it to a nearby O'Reilly's. They tested alternator and battery. Battery was good but completely drained, alternator was fine (they tested it with the truck running, not the alt off), but they said they got a code for "failing voltage regulator".

So, I told him to take 2k off the price, I got a deal, jumped the truck, and it made it home fine. Wouldn't start again. I ran over to the auto shop and got a new battery and it seems that the battery and alternator and everything is working fine, but 5 mins into putting a load on it (driving, accessories, etc), the Check gauges light comes on and I get code P1682 on the dash when I pull the codes.

Now my question:

Do I assume it's the voltage regulator? Because that is in the PCM and I really don't want to drop money on that right now. I have parts coming to do an external voltage regulator on Tuesday and MIGHT set that up if I can't find the problem.

Checked grounds, there is one nasty frayed cable that looks like the fan hit it or something that I am replacing tomorrow, going to see if that helps it. Replaced 140A alternator fused, that thing was nasty old and blown. It cleared the code but same problem came back again after driving for 15 mins. Going to check tomorrow as well to see if I blew it again.

What about the alternator? could the test O'Reilly's used be wrong? maybe voltage isn't being regulated because the alternator is just barely hanging on?

Any help would be greatly appreciated, sorry for the long a** post.

 

If you are blowing the 140 amp fuse, you need to find out WHY. I think that is the first thing I would be looking at.

Welcome to DF!