Speedometer and fuel gauge replacement tips?

[gordyzx9r]

Originally Posted by VetteVet

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The needle should go past full. The gauge works on variable resistance, from zero to ninety ohms. Zero Ohms will read empty and 90 ohms will read full.
As the float arm rises it raises the fuel gauge needle towards full. As it drops the gauge resistance reads near zero ohms and empty.

If you remove the sender wire from the tank unit and the gauge goes past full, it means the problem is in the sender unit. Your float arm may be stuck or the float may have pinholes in it and be full of gas.

Take the sender unit out of the tank and ground the sender flange to the cab or another good ground and with the key on, raise the float arm up and down and watch for the gauge to follow the movement. If you don't see any needle movement then the sender is bad or the float has pinholes in it and is too heavy to move up with the gas. You do have gas in the tank right? .

There is definitely gas in it...I'll try what you said and see how that goes.