Check Gauge Light, Battery voltage spike, erratic speedo readings
 

My 01 Ram 1500 instrument panel has been acting up. At first my check gauge light came on and my battery voltage spiked. after i stopped the truck the light went off and went to normal. on the highway the same thing happened but this time my speedo started to bounce around i was doing 70 and it went down to 50 then started to bounce down to 0. Are these problems related? I installed a new battery yesterday and a new alternator 3 weeks ago.

Thanks!

Mark

What I also forgot to mention was that I have a P1757 code. Im thinking the speedo behavior has something to do with my speed sensor/governor sensor, hence the code.

What prompted the battery and alternator replacement?

I replaced the alternator because the battery meter dropped to 8 volts and it was making an awful bearing noise. it also smelled like the alternator was burning. I had just replaced it a year before. I tested my battery and it wasn't putting out the cca that it was rated for, also it kept building up corrosion.

Batteries will build up that white crap no matter what you do. :D

Pull the alternator, and have it load tested. If it tests good, likely your voltage regulator is having some issues. Unfortunately, the voltage regulator is part of the PCM......

98 and newer trucks need the VIN flashed to the PCM, otherwise, it gets annoyed. :D