My check gauge light comes on and pegs @18 when rpm’s are higher after running for a couple of minutes. Then I shut off motor it will go back to normal? I have a 2001 ram 1500 5.2 with 94,000 on it.

 

Failing voltage regulator, which, unfortunately, is part of the PCM. You can either replace the PCM, or change over to an external regulator. (cheaper......)

 

I was afraid of that hopefully my shop will find a frayed wire or the voltage fuse in box going bad.

 

Well results are in and it’s hard to believe that my shop ran it through the ringer and the best they could come up with is that my battery gauge might be sticking and a replacement one might do the trick. They said All my electrical components checked out at the correct volts all grounds were good and voltage regulator is good.

 

That's just odd..... A gauge failing is incredibly rare......

 

May be a issue with the pcm or cluster. My volt gauge reads low sometimes and others it's fine. Try the cluster test.

 

I would rig a stand alone volt meter that comes on with the ignition. 18 volts, actual, will fry your battery and many electronic components.

 

Well good news gauges light has not come back on since mechanic found some rust on negative battery cable at the battery.

 

wow that's cool I will try that .thank you so much

 

Check all your connections. Grounds are bad about corroding at the frame. You can't see that unless you go looking. Get a small tube of dielectric grease and clean the connections and you might notice a lot of things are working better.