Your sending unit may be fine, but yes they can go bad. Most of the time it is a ground issue if it doesn't work. The fuel line along the frame is steel, but to install it with the body on the frame the body has to be lifted up some. There is a rubber hose between the end of the steel line and the gas tank that connects to the sending unit. The fuel line runs down the right side of the frame on my 70, I believe that is true on a 69.
