Hi Kid, I also have a 48 gmc 1/2 ton. When I got my truck the wires to the temp sending unit were cut and it is electric as you say. It looked like the original sending unit but when I tried to find a replacement sending unit and gauge I could not. So when I replaced my gauge cluster I had to go with the mechanical kind so I changed mine over. It works great and it seems that everyone I’ve seen runs the mechanical type. Good luck!