Well, heres what I found out. This unit also works the idiot light. We couldn't figure out why the hole in the other head was pluged and assumed it had been done years back and the light just wasn't hooked up. because there is a wire on the left side that looks like it would be for the temp light. But we grounded it and the light did not work. After some time we discovered that the light is controlled by the 3 prong sending unit (3 fuses later)
The light is controlled by the single prong that is perpendicular to the two parallel plugs. Thanks for all the help. We ended up replacing the original and cut off the plug and are using only the temp light wire.