Getting at my AC Blower Switch (66 Polara)

[Fishfan]

As I mentioned in another thread, my blower only work on high setting. I thought it HAD to be the blower motor resistor. But after shelling out $90 on an NOS part it looks like it HAS to be the switch.

Any advice on how to get to the switch? My FSM doesn't give me a clue (unless I'm looking in the wrong sections)