[mike y]

How does it work? It starts at the sender with 1 wire when you get to the gage you have 3 wires, mine pegs out when you turn the key on same thing when running. HELP this is 91 stock mustang. Thanks Mike

 

[fiveliter8]

Well, if my brain synapses are functioning properly, I think two of the wires are for power to the gauge and the single one from the sender is the signal.