Had to cope with the blower switch problem earlier this year. I don't know if your car is exactly like mine, but you may want to check. Mine has a cable that goes from the switch to the vent behind the glove compartment. These cables have a tendency to freeze up and make the switch hard to turn. I didn't find out about the cable until it was too late. Mine got more and more difficult to turn and finally, I broke off one half of the switch shaft one day. Had to replace the switch. You don't want to do that if you can help it!
If the cars are identical, I would first find the cable behind the glove compartment, take it loose and try to coax some penetrating oil into it. You may have to pull it behind the heater box over into the driver's side in order to elevate the end and get the oil to run through. Whatever you have to do and however long it takes, work at it. It will be worth it if you succeed.
If that fails and you have to take the switch out, I had to remove the driver's seat, center console, carpets, radio, ash tray, etc and seem to recall having to remove at least one of the heater switches to get enough working room to R & R the fan switch.
Hope our cars are similar enough for this to be of some value to you. Will attempt to answer any questions you may have if I can.
If they are not similar, sorry to have misled you.