Have a 2002 Dodge Ram 1500 that I bought about 7-8 months ago that has 59000 miles on it. The fuel gauge works occasionally when full but when it gets low, usually 1/2 tank the gauge hangs up and stays there. I thought at first it was the fuel pump/sending unit so I bougt a new one and before putting it in the tank I plugged it up and moved the float arm and it has no affect on the gauge so I just left the old one in the tank knowing it wasn't the sending unit. I did take the old one out and examine it just to make sure there was nothing wrong with it while I had the bed off the truck. Got everything put back together get back home and the gauge works flawless for 2-3 weeks and then it is back to working occasionally. It like it could be in the wiring, my friend that help me take the bed off (he is a mechanic) made sure the the wires/connector that plugs in the top fuel pump was clean and all connectors were tight and that all the woltage was good. To me is seems like a bad ground somewhere. What do you think? I would like to get a wiring diagram for the fuel system but don't know where to get one. I hate when something isn't working good and especially a fuel gauge. I rarely drive the truck due to being a K9 officer and having a take home Expedition so the truck gets maybe 2-3 thousand miles a year put on it and all of that is pulling a bass boat but man it drives me nuts.

 

I agree, sounds like a bad ground somewhere in the tank area.

 

bad ground is the most likely

if memory serves me right a model year 2002 Ram "might" be wired so that the PCM computer has to read the float level voltage from the resistor strip, then the computer drives the entire set of dashboard gauges.

Earlier year Rams had the fuel float level resistor strip directly wired to the dashboard tank gauge.
Try to confirm which way your Ram is instrumented.