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what is the problem with the one you have?
Unless you get lucky and find the part number and then the gauge itself, you may have to buy a used instrument panel and pull the gauge out of it. http://www.ebay.ca/itm/87-91-Ford-EC....c100033.m2042
Both tanks read empty, have to watch the odometer so I don't run out of gas. I don't think both sending units could be bad at the same time. I looked at Ebay yesterday, but searched fuel gauge, when I should have searched gauge cluster. Thanks for the tip, I might just buy this one you sent me.
Have you done any trouble shooting yet? There are several things that could be the problem besides the gauge itself.
This is a diagram for a 1988 so I am not positive yours is exactly the same. The wire colors may also be different but it should be at least similar.
Question. Does your coolant temperature gauge and oil pressure gauge work?
On my 85, where the main harness connector plugs into the back of the instrument panel, the printed circuit board is damaged. Part of one of the little thin copper connector tabs on the circuit board was missing. I had to solder in a jumper wire to repair it.
You could also have a problem where the printed circuit board connects at the gauge itself.
The selector switch itself can be bad or the connector to the switch can be bad. When you flip the fuel tank selector switch, it swaps back and forth between the front and rear sending units but there is only one wire from the switch to the gauge. The tank selector connection is labeled C134.
There is another connector back at the tanks C100. Unlikely but you could have a bad connection back there but that would mean that the connector pins for both tanks is bad.
Again unlikely but you should also check the ground connection at both tanks. If all the ground connections meet under 1 terminal, there could be come corrosion there.
Again unlikely a broken wire from the selector switch to the instrument cluster connector.
So there are several things that can cause the problem.
Note, I have read not to apply 12Volts directly to the gauge as it can damage the gauge. In the drawing you see what is called IVR (instrument voltage regulator). The IVR is supplied with voltage when the ignition switch is turned to the on position. If I remember correctly the gauges operate on around 5 volts. The IVR sends 5 volt pulses to the gauges to operate them, that is where they get their power from. So all the rest of the wiring, selector switch, and sending units are operating the ground side of the circuit to the gauges. I have read to not just ground these circuits when testing them unless you are working with the frame ground directly after the sending units. The sending units themselves work like a resistor so anything between the sending units and the gauge itself, you need to use a test light so the bulb in the test light acts somewhat like a resistor.
(Somebody correct me if I am wrong)!
This guy says it is a Blue and yellow wire from the switch to the gauge but don't know what year his van is. My 88 diagram shows a yellow with a white stripe. He did not use a test light, I would to be on the safe side.
