Gas tank sending unit wire

[Trailering Special]

Can anybody help me with a gas tank sending unit problem. I have a 78 scottsdale with dual tanks. The passenger side sending unit went out some time back and i am just now getting around to fixing it. As i dropped the tank and unhooking the hoses and wires i noticed the sending unit wire was totally gone except for the little connecter on top of the sending unit with a very small piece of wire coming out of it. I cannot find the original wire connecting to the sending unit on top of the tank to the truck harness.