Fuel/Water Temp Gauge Issue Found! Now what...

Unplug the the gas gage sender wire at the gas tank. Then jump the sender wire directly to chassis ground, and turn the ignition key to the run position. If gas gage goes to full, your gage and wiring are good, and your sender unit is bad. It's really as simple as that. You can test your factory water temp and oil pressure gages exactly the same way. Do not leave the key on longer than you have to with it ground shorted like this. Only to test gage deflection.

If gage needle doesnt move at all then you have other issues either with gage or wiring. Sender wire shorted to ground and everything else being good, the needle will go all the way to the high end.