Heater fan switch wiring

I'm working on my brothers 65 trying to get the heater hooked up.
The heater was not hooked up when he got the car so I am not sure about the wiring for it.
I think I found the plug that go's to the switch but that is all.
Is there a pigtail that runs to the resistor from the switch or will it come from somewhere else?
If someone could send some pics and diagrams that would be great.
Thanks...

Vintage Mustang Wiring Diagrams

Welcome to the board.

Try the search function under "wiring diagram" this was posted recently by yours truly. Good Luck