It is easier, Kevin to just use the signal wire (assuming it goes to the gauge in good shape...which our OP has said he checked). Here's why I say that: The coil on the left of the fuel gauge is referred to as the choke coil and the other (on the right side of the gauge) is the operating coil. When you turn on your ignition, current runs from your battery through the choke coil and also over to the operating coil via the common connection between the two coils. Once it arrives at the operating coil, some current runs right through and to ground. This energizes the choke coil and the operating coil to an extent. Some more current at that junction runs back to your fuel tank and through the variable resistor that is your sending unit. And here is where the magic takes place. If you recall, this sending unit will register 30 ohms of resistance when your tank is full and 0 ohms of resistance when your tank is empty. When there is less resistance, more current will flow through the choke coil and the choke magnet will be stronger, pulling the needle to E. When there is more resistance, then more current is pushed into the operating coil and then this coil's pull will overpower the choke coil, pulling the needle toward F. And since the resistance is variable, varying degrees of resistance will cause more or less current to be in that operating coil and the needle will be pulled more or less toward F (or toward E) proportionally. So by connecting common resistors between the signal wire at the sender and ground, we'll simulate a working sender...in my suggested case with half full and a bit more than completely full.
Last edited by Jon G; 09/20/20237:06 PM.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
