Binary A/C safety switch voltage

[jdhcth]

I have installed my NAP Underdash unit in my 67 and I am about to vacuum/charge the system.

I mounted the Hi/Lo(binary) switch on the drier. I turned the ignition on and checked the voltage at the switch, not hooked to the compressor yet btw, and I have no voltage or a very small amount there, like 0.12v. I turned the fans on and turned the thermostat full cold....no change in voltage.

Question is: What voltage should I see there? What voltage does the compressor require from this switch?

It's fed off the same 12 volts as the fans, which work fine.


Thanks,
JD