I knew that I had a set of heads from my 75 Formula in the garage someplace so I went looking for them and found them. The sender was still there, pretty exciting. I pulled the sender, cleaned it up and that is when I noticed that the black plastic insulator was cracked. I don't know if it will work but I will soon.
It cleaned up well, the markings on it are, AC-MADE IN USA-12 VOLT
Crack in the insulator