Help with why gas-gauge is not working?

[Crist Clapper]

Disclaimer: I'm not technical. :patriot: What are the most common reasons a gas-gauge does not work?

[denverd1]

bad ground to the gauge/pump *I think*. Mine only works when its low. top it off when I go ride and it works for me!

[4.3LXJ]

Crist, the way it works is that when you turn on the key, power goes directly to the gauge. Then through it to the sending unit. The unit then acts as a variable resistor, changing as the fuel level changes. The power goes from there to ground. If the gauge doesn't work at all, then probably the power is not getting to the sending unit. If it only works a little or incorrectly, then it is usually a ground issue

[Crist Clapper]

Poked around a bit today... No progress. Trip to the local mechanic for help.

[Brasscatz]

Mine is off by quite a bit, I think I need a new float which on mine is part of the whole fuel pump/filter assembly in the tank and isn't a cheap part

[nickyg]

mine always reads a quarter a tank lower then whats in it. example. full tank shows 3/4. It drove me crazy for a while now I'm use to it.

[Crist Clapper]

What I learned: The gauge-needle is moved by magnets driven by 1-ohm to 88-ohm(full-tank). Applied voltage... Watch the needle go ♬ up-and-down, up-and-down ♬. Cleaned terminals on sending-unit and applied dielectric-compound. All is good in Désirée land again! :driving: