Need some help on the stock A/C wiring

[Project1970]

Okay...I go through a blower motor switch every year, if not more often, and I'm sick of it...

So, what I want to do is bypass the stupid thing altogether and run the fan off of a relay, no speed control, but I don't care. The only snag I can think of is how is the A/C compressor turned on when the switch is in any position other than OFF? (I say that because my HI position is disconnected at the fuseblock (wiring gets too hot) yet the A/C compressor is still engaged...)

This is more or less an extended stopgap fix until I can afford a Vintage Air unit.