I have an '03 Ram with the 4.7L. My speedo needle jumps around between 0 and 15 mph in park and in neutral. I am also getting the brake and ABS warning lamps. The engine rpm is also jumping up and down in neutral, in gear while not moving or in park. I suspected the rear wheel speed sensor so I changed it and it made no difference. I also unplugged the lead to the speed sensor and obviously the speedo needle does not move. The engine rpm does not bounce up and down like it does with the lead connected. The brake and ABS warning lamps are also not on.
Is there anyone out there who knows what the probem could be?

MXRev

 

Sounds like maybe a cluster problem. Is it still under warranty?

 

I had the same problem with my 03 HEMI and I took it into the dealer. They had to replay the whole cluster.