I recently picked up a 1959 Ford Ranch wagon. I do not have a working fuel or temperature gauge. When I purchased it, the fuel gauge would read 1/4 tank no matter what level of fuel was in the tank, full to drained and completely empty. When I would start the car, the temperature gauge would immediately climb to the “H” and pin itself to the right side. I tested the constant voltage regulator on the back of the gauge panel and found that both terminals on the regulator were reading just over 13 volts when the car was running. Clearly, the regulator was not dropping the feed to the gauges down to the desired 5 volt range. I swapped out the regulator and now I get zero readings on both the fuel and temperature gauges. I tested the terminals on the renew regulator and found 13.2 volts going in and 5.06 volts going out to the gauges. I then tested the volts on each power terminal going into each gauge and at normal engine operating temperature. The power feed going into the temp gauge reads 5.03 volts and the terminal on the back of the gauge that is fed by the sender wire is reading 3.6 volts. Seems like the resistor in the sender is doing its job. The power feed going into the fuel gauge reads 5.03 volts and the sender terminal reads 4.7 volts. (Tank was filled approximately 25 miles ago so it is nearly full) Additional tests I did.... I removed each gauge from the panel and tested it independently by attaching the positive side of a 3 volt battery to one terminal and the negative side to the other terminal. When I did this to the fuel gauge it read 3/4 full. When done to the temp gauge, it read just under the hot “H” mark. Therefore, both gauges are working. I removed the wire going to the temp sending unit on the engine and grounded it and the temp gauge immediately climbed to the “H”. I swapped two different temp sending units into the engine block and reattached the wire and both rendered no reading on the gauge. Lastly, I removed the sender line going into the fuel gauge while it is running and nothing happens to the gauge, still reads completely empty. I’m at wits end.... not sure where to look now to diagnose. A ground somewhere? I found a separate ground wire run from the back of the gauge panel to the bottom of dash that was there when I purchased the car. I undid it and saw no change at the gauges. Any advice is GREATLY appreciated.