1958-1966 Thunderbird constant voltage regulator
Little gizmo under/behind your dash that regulates the voltage to your gauges. This voltage regulator is just like the ones FORD used originally. They actually pulse the 12 volts half the time. The gauges in your car are actually 6 volt gauges. You can not test your regulator with today’s digital multi-meters because they will not react fast enough. So 12 volts go in and a pulsed 12 volts comes out. Since the gauges are like mini heating elements they will each warm up to the proper spot. The ground must be connected for any of this to work. That is the base must be screwed in or if you are bench testing one of these a ground must be connected to the case. If the unit is not grounded it will put out the full 12 volts all the time. Once it it properly grounded you can test its function with a test light not a meter. So on the input side the light will glow and the output side it will blink.