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1979 Mark V Fuel Gauge, Sending Unit Questions

Hey Bill,

I have a 1979 Bill Blass Mark V I just bought 4 months ago and the gas gauge doesn't work (not digital). So I jacked the back end up and turned the key to "on." With the sending unit plugged in, the needle moved to almost "E." I unplugged it and the needle didn't move at all. What does all this mean? Attached is a pic of the unit, but I'm perplexed because you can see it only has 2 of the3 prongs. Can it still work if it only has 2 prongs?

Thanks again,



Hi Paul -

From your photo I can't determine if your wiring plug has two or three wires to it to match the sending unit. If there is only two wires on the female plug then it is correct and should work. I also cannot see in the photo if one of the male pins is missing or if it is a correct blank off third pin style as designed and is a two wire unit.

The best way to test the fuel gauge circuit is the method that is shown in the1979 factory shop manual. However we find that many of these in tank sending units have due to age corroded badly and require replacement or repair. From the appearance of your tank unit it would not hurt to remove and inspect it. It may be badly deteriorated and/or the float could have developed a leak and rendered it useless. If you do not have a shop manual or the test equipment, we would offer to test your sending unit and advise you further if you could remove it and send it to us. Call our office for more information.