Hello,
I Just recently purchased a 99 2500 24 valve cummins automatic (hard time finding a manual) anyways I took the truck in last week because my rpm gauge was and wasn't working from time to time along with the fuel gauge on the dash. They replaced the battiers with new ones.apparently there was hardly any charge to them. But two days later I filled the hog up when it was reading half full, when I started up and the left the gauge did not move. Still stuck at half. Is it somthing else? Possibly a ground wire? Anyways I'm new to the diesel world so be easy on me.

Thanks have a great day.

 

Possibly the fuel sending unit in the tank. Wouldn't have anything to do with the RPM gauge, but the issues may not be related. This is a barbaric test, but it may let you know. If it gets stuck again, kick the hell out of the bottom of the tank. The shock wave may change something in the tank and change the reading. A lot quicker than back probing the sender unit wires to see what they are reading.

 

Had to take it back in. Was having a hard time starting after I was driving and warmed up. Don't know what the problem is now.