I am redoing the PO wiring mess on my 1964 Ford F250. There was no temp or gas gauge working and the the wires were not hooked up. I have got the new Instrument Constant Voltage Regulator. The Service manual shows only two posts. The one that I have has three. Two Blade (Male) and one Slot (Female). I have the a V shaped wire that is the feed for the temp/gas gauge It connects with the two wires terminating in to a blade that goes in to the Slot of the CVR. I have one Feed wire that terminates in to a Slot, I believe this goes on one of the Blades, but I still have one blade left open on the CVR.

Is this correct? If it is then what is the second Blade for on the CVR? Could it just be a left over for other other car applications?

 

all ford CVR's i have ever seen only had 2 contacts.

 

I don't know what model CVR you have, but the ones for the 80-up trucks do have 3 connections. In, Out, and Ground. Ground might be where the case bolts down in some applications.

This thing works like a turnsignal flasher. When you read the output voltage with a meter, you will see the voltage blinking on and off. They also usually use it in conjunction with a resistor in the circuit.

The factory gauges are very slow to react to changes of any kind. So you won't see them bouncing up and down with the blinking voltage they are being given. The CVR changes the duty cycle of the voltage coming in, and that effectively regulates them.

As the voltage in the truck varies from the alternator and all the loads presented to the electrical system, more or less voltage is supplied to the heating element inside, and it heats faster or slower. The heating element is wrapped around a bi-metal piece like in a toaster. This bi-metal piece curls up and down and it has a electrical contact on one end. When the bi-metal curls, it breaks the circuit. It breaks the circuit faster or slower, and this effectively regulates the power to the gauges keeping them steady.