Yet another fuel gauge issue...solved!

[leddzepp]

The fuel gauge in my 68 worked up until recently...then it suddenly "froze" at 1/2 tank. I unplugged the sending unit wire at the fuse panel...nothing. I tapped the gauge cluster, wiggled the plug, still nothing. I create my own sending unit wire and ground it...nothing. There is power to all other gauges so I assume there is power to the fuel gauge (in hindsight, at this point there was not). I assume it's a gauge problem, so I remove the gauge and rig up some wiring and connect it up to a car battery, and it zero's out (works). I then pull the sending unit and wire it into the gauge setup I created, and move the float arm...the gauge responds accordingly (it also works). I reinstall everything and the gauge pegs out, past full at 3oclock. Once again, I attach a ground at the fuse panel and the gauge stays pegged. Now I'm CERTAIN I have power and there must be a break in the sending unit circuit between the gauge and the fuse panel. I'm "guessing" a crack in the circuit board, or less likely a break in the wiring from the plug to the fuse panel. I inspected the board with a small dentist mirror, and the plug (I never removed the entire cluster) and all looked well. Just for grins, I decided to use a small jewelers screwdriver to "bend back" the number 4 prong (sending unit wire) pictured below, to make sure it had contact with the circuit board when plugged in. PROBLEM SOLVED!! I also went back and did the same thing to number 3 prong (power wire) to ensure the gauge does not lose power and freeze again. In the end it ended up being a double whammy

Just thought I would share this, as every thread and FAQ I searched on the subject mentioned a faulty sending unit wire, faulty gauge/resistor, faulty sending unit. Hope this helps someone else that can't get their fuel gauge problem diagnosed before buying new parts that aren't necessary.