When I got the '93 Cherokee Country, only the high speed setting would work. It finally went out.. At junkyard -three out of three switch harnesses (where the wire bundle connects to hi/med/lo fan switch) were melted.
the diode on the resistor was fried.
As it turns out, the switch was wired incorrectly. I placed all of the wires according to the factory book. I now have high/ med 1/ med 2/ low.
AND i changed the burned out 30 amp fuse with a 25 amp. as it should be.
AAHHH... a/c is a wonderful thing.....it's here to stay..... Good Luck y'all......