Fuel Gauge not working

[RogerDodger]

I first tried to ground the wire at the sending unit to get a reaction at the gauge. I checked for power at the sending unit and there is none. I have power on one side of the fuel gauge but not at the blue wire going back to the tank. Does this mean the gauge is bad? 

[Tilar]

You won't have power at the sending unit. The sending unit works by resistance to ground. The sending unit is actually just a variable resistor. The more fuel there is in the tank, the less resistance to ground it will show and the gauge will go up. As the fuel goes down, it will raise the resistance to ground and the gauge goes down.

A simple way to test the sending unit is to hook a test light to positive battery on one end, and the other end of the test light to the wire going to the unit. If it has a full tank or close, the test light will light up almost to full brightness. If it is low on fuel, chances are it will be very dim.

You can also have someone take the wire off of the sending unit, and tap it to ground while you watch the gauge. I wouldn't just hold it down there because there would be no resistance and will probably trash your meter.

[y3chargerrt]

Either your gauge is bad or the wiring to the sending unit is open. Thats assuming when you keyed it on and grounded the connector there was no movement of the gas gauge.

[Plumcrazy]

You won't have power at the sending unit. The sending unit works by resistance to ground.

You should have power at the sending unit.  It should be a pulsating 12v.

Pull the cluster out enough to gain access to the backside of it, also add a jumper wire to ground it.
If you have power at one of the gauge posts but not the other then the gauge is bad.

If you have power at both posts you may have a broken pin for the electrical connector on the circuit board