1940 temp sender test?

[BillM]

Connect the terminal on the sender to one terminal of the gauge and the other terminal of the gauge to 6 volts; ground the body of the sender. Polarity doesn't matter for a test. Temperature gauge will go from Hot to Cold when power is on with the sender in the circuit. As the sender is heated up the points inside it momentarily open and the gauge starts to go back to Hot. If you have a test light you could wire it in series with the sender and see it blink off briefly as current flows through the circuit.