[JSeery]

There is a difference between the original senders and the current ones. The latter are resistance type and the originals worked by pulsing the current. However, a resistance sender still should provide some type of reading on the gauge. The sender is providing a ground to the gauge, so to test the wiring connect the wire at the sender to ground for a short period of time and see if the gauge shows a reading. Another issue could be the sender being the wrong resistance for the gauge.

The original temp sending units were a single contact and a dual contact. The dual contact is just an on/off switch and would not be used in a non-flathead application. Again, the single contact sender is providing a variable ground to the gauge. If there is a non-conducting sealant on the sender threads it will not ground properly.