Have you inpsected or done anything with the AC/Heater controller? There are two fuses in the circuit, one for the blower motor and the other for the AC controls, which is blowing? I would disconnect the 6 wire harness from the AC controller and check the pigtails Tan, Black, and Brown wire for shorts to ground. The black is feed so its probably okay since the fuse doesn't blow til you hit a selection. The selector should turn on the blower, without moving the blower motor speed control, but it does feed the tan wire to the blower switch, so while you have the harness apart, remove the 3 wire blower motor harness and check for grounds between the ends of the tan wire on the 6 wire and 3 harnesses. Do you have the electrical diagram?