1959 Fuel Gauge Troubleshooting

[PaulB]

My fuel gauge is not working and from other posts i have read the trouble could be a bad gauge or a bad sending unit, or a short or disconnection in the wiring. So I want to check the electrical issue first before i attempt to replace the fuel sending unit in the gas tank. I understand if I use a voltmeter and there is no power is going to the gauge with the ignition on the gauge is defective and needs replacing or a short in the wiring. If there is power its likely the fuel sending unit in the tank is bad.
So my question is; is there a way to get to the wires behind the fuel gauge on the instrument cluster? I see two screws at the bottom of the aluminum cluster panel. If i remove those screws will it pull out enough to get to the back of the gauges to put a voltmeter on them? If not do i have to pull the entire dashboard?

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[74 Harley]

If you don't have power at the gauge your problem is between the fuse box and gauge.
The sending unit is a variable ground. That's how your gauge makes a reading. If fully grounded it reads full.
What does your gauge read, what does it actually do? Or not do...

 

[oldcarguy34]

My fuel gauge is not working and from other posts i have read the trouble could be a bad gauge or a bad sending unit, or a short or disconnection in the wiring. So I want to check the electrical issue first before i attempt to replace the fuel sending unit in the gas tank. I understand if I use a voltmeter and there is no power is going to the gauge with the ignition on the gauge is defective and needs replacing or a short in the wiring. If there is power its likely the fuel sending unit in the tank is bad.
So my question is; is there a way to get to the wires behind the fuel gauge on the instrument cluster? I see two screws at the bottom of the aluminum cluster panel. If i remove those screws will it pull out enough to get to the back of the gauges to put a voltmeter on them? If not do i have to pull the entire dashboard?

Pull the chrome bezel that covers the guage toward you. Remove the 3 or 4 small screws that fasten the gauge to the dash and carefully pull the gauge out partially, there will be two angled slip on connectors directly behind the fuel gauge. One goes to the cvr attached to the back of the dash and the other goes to the fuel sending unit in the tank. There are similar connections behind the temp gauge and also 2 bulb sockets to illuminate the gauges. Depending on the length available of the wires, you may have difficulty gaining access, if so, try to wiggle or disconnect them to get more room.

 

[PaulB]

If you don't have power at the gauge your problem is between the fuse box and gauge.
The sending unit is a variable ground. That's how your gauge makes a reading. If fully grounded it reads full.
What does your gauge read, what does it actually do? Or not do...

The needle on the gauge shows empty and does not move. I just filled the tank with gas over the weekend and the needle still shows empty. I understand the problem could be between gauge and fuse which is inline right, not a fuse box? But how can i reach the back of the gauge to test gauge or wires for power?

 

[74 Harley]

One thing to remember, since you have No reading it could also be a broken or disconnected wire that hasn't grounded out.
Once you get the gauge out and determine if it has power ground the other side to test the gauge.

 

[doug7740]

Since the gauge shows empty, before you remove the gauge from the instrument cluster why don't you ground the wire that goes to the sending unit in the fuel tank. If the gauge reads full after grounding the wire, the problem is the sending unit in the fuel tank and not the gauge or the wiring.

doug7740
1955 Thunderbird Blue

 

[jack-in-sac]

This may or may not be useful: When your fuel gauge does not work does your temperature gauge red variably as the car warms up or is it all cold or all hot. By all hot I mean is it pegged hot? Up through the 60s Ford used a behind the dash regulator for aproximatel five volts in powering the fuel and temperature gauges. when tha little guy fails the fuel tank goes to zero reading and the temperature gauge goes to maximum.