Temp gauge wiring

[mecwpri]

Started on my latest find, a 1965 3/4 ton LWB. I strarted on the cooling system as the previous owner attempted a radiator swap and held the radiator in with a rope, well it broke and fell into the fan, imagine that! I found a good radiator in the wrecking yard for a V 8, so I picked it up along with all the original mounts and installed it, new hoses and thermostat for good measure. I ditched the old broken capilary tube gauge thing and installed the proper electric sending unit. My question is which colored wire goes to the sending unit as most of the factory wiring has been upgraded, if you can call it that by the previous owner. The gauge has 2 wires pluged into it but I dont know which one goes to the sending unit, also where does the other wire go? 12V? any help would be appreciated. Will post some pics as soon as I can talk the wife into letting me have the camera for a few minutes.