Hey all, I just replaced the in cab gas tank in my '75 crew with a between the rails '79 tank. The existing "hot" wire is orange the new tank has 2 terminals sticking out, any idea which one is hot???? In case you are wondering how I fit the tank between the rails-I just turned it the other way and fabricated new mounts. thanks

 

I'll have to look tomorrow, but i really dont think it matters being it just measures resistance

 

The terminals are mounted at roughly 12 o'clock and three o'clock. The 12 o'clock is the ground. In the first picture you can see the location of the ground stud from underneath.

 

A big thank you! Pics and all! You just cant beat this site and the people on it!!!!!!

 

Glad to help out

 

If the gauge side would have been connected to the ground terminal the only thing that would have happened would be the fuel gauge would read full all the time. No damage done.

 

Diesel_Brad is correct in theory because all the sending unit is, is a rheostat - however, because one side of the rheostat is tied to the sending unit body, there is a chance the body could receive a weak ground through the tank. In that case, reversing the wires could peg the gauge full as Mike described. Therefore, in practice, Mike is correct.

The original factory pigtail is keyed, for this purpose. It should only go on one way. The plug is shaped like a heart.