Horrible floating gas gauge

Yeah, that's a little off. Next time you'll know when it says you have 20 gallons left to go right to a gas station.
How big of a tank do you have? I didn't even know there are sensors that measure gallons. That speaks volumes about my expertise- expert tease. But I only answered to advise you to give some specifics about your rig, make and year, for a better chance at a good answer.

The fuel level sending units to gas gauges on cars and light trucks work like this: a low voltage signal of about 5 volts is fed through the gauge on the dash and then to the sending unit in the tank, where the float arm connected to the unit varies the resistance to ground by its position in the tank. As the float moves up and/or down it mechanically increases or decreases the amount of resistance to ground that the sending unit has built into it. The 5 volt signal goes through this variable resistor and then to ground, either right there or through a ground wire back out of the tank and to a common ground point. The needle on the gauge precisely registers that resistance...well, pretty close, that is. The temperature gauge works in a similar fashion. But that is in a nutshell how the fuel gauge circuit works. Don't know about yours, Don, sorry to say. Good luck with it.

You are going to need to do some basic troubleshooting. First, check to make sure you have voltage at the gauge. If you have a minimum of 6V (DC) across the terminals of the gauge, but the gauge is not reading, replace the gauge. If you have <6VDC reading at the gauge, check for voltage at the float unit on the gas tank. If <6VDC at the gas tank float module, replace the float module. If you have voltage at the float module, suspect a problem with the dash cluster display.

works off the dash power. easy way to find out if its the dash or the float in the tank. turn ignition on off and on again looking at the gauge should see it move a bit. if not then there can be a fault from the wiring to the float. can even just be the conector on the tank..

Sounds like the float is stuck, or corroded. Look to see if you have an access door above the fuel tank. If so you should be able to take out the fuel sender, unstick the float, or clean the sensor, and replace it

Something is wrong with the float or the sending unit.Did anyone replace the fuel pump lately.

Talking about fuel gauge issues and how do you how do you diagnose, ... is the dash unit right here, and obviously the gauge doesn't read correctly. ... to fix the fuel gauge, so you can actually fix the fuel gauge electronically by reflashing the program. ... How to Troubleshoot a Malibu Fuel Gauge & Dash Light Not Working ...Could be a bad fuse - fuse # 17 is a 15 amp fuse for the fuel gaugeCould be a bad float on the fuel gauge sending unit inside the gas tank ( it's with your electric fuel pump ) If the float gets a pinhole or crack in it , the float fills with gas and sinks so the gas guage reads empty all the time Could be a wiring problem

This is a case of the sending unit being bad, this is very common on these trucks, this is like a toilet float, it floats inside the tank with a sensor at the base that controls the gauge, hope this helps,

make sure you fuel tank float isn't becoming saturated with gasoline. If the gauge reads full when it is indeed full, you probably don't have a short in the wire that goes to your fuel float sending unit. If that wire is bare and shorts out it will say you tank is empty since it works on resistance open or unplugged the gauge would read full, closed is or going to ground the gauge will read empty. I would think the float might be bad or the float arm got stuck down when you turned a sharp corner. I had one of these cars but I don't remember exactly where the fuel level sending unit is located and if you need to remove the fuel tank to gain access to the sending unit. I hope this helps you

you either have a bad sending unit, which iit is in the fuel pump assembly in the tank or a hole in the float and it fills with gas and sinks, which it's also on the fuel pump assembly in the tank or a bad fuel gauge in the instrument cluster. it's more than likely a sending unit problem, jeeps are bad about the sending unit to quit working

u will have a faulty float in fuel tank