I have a 2001 Dodge Ram 1500. I bought it a while back from the original owner. The truck was in great condition and ran great! The transmission went out a few months back. After replacing the transmission, it went out again. With the third transmission it has been running great again. Two weeks ago the "check gauges" light came on and the battery gauge went all the way to the right. It stayed there for about five minutes and then went back to the middle and the "check gauge" light went off. This cycle repeated itself every five minutes or so during my 45 minute drive. Had it checked, just needed a new battery. After replacing the battery it was fine for about a week and it started up again. I replaced the alternator and it ran great over the weekend. Now, on my way home today it started happening again. All the other gauges are fine. Does anyone have any other ideas? What would you try next?

 

Check gauges just means look at the gauges because something is out of the normal range, in your case the system voltage. The "why" requires a more investigation. On these trucks the alternator output voltage is controlled by the PCM by means of a PWM signal to the alternator. If that PWM signal goes constant full voltage the output rises to maximum which is what I think happened. Either the PCM voltage regulator is going bad (although the typical failure is no control voltage not full voltage) or there is a wiring issue.

 

Spam ^^^

 

Yep, and she is history.

 

Good