1974 3/4 ton Fuel gauge past full

[mntoy]

I just replaced my starter on my 1974 3/4 ton and in the wire loom that went to the starter there were 2 additional wires. This truck has dual tanks, and one wire (looked yellow) went close to the fuel switch over valve and then crossed over to the drivers side of the truck and into a different wire loom that appears to go back the the cab. When I put the starter back in I forgot to hook up the yellow wire and here is where my problem started, the fuel gauge went well past full when I turned the ignition key forward but did not start the truck. So I went underneeth and hooked up the wire and the gauge is still well past full. There was also a second wire (looked yellow) that was cut and appeared to go nowhere in the same loom by the starter wires which is stll not hooked to anything. Any ideas what is the matter with my fuel gauge? and how to fix it?