Remove the blower housing and put the bolts in a safe place. Replacing these will cost more than the switch. Remove wires and install wires on new switch one at a time. Once both wires are installed remove switch mounting screws and install new switch. Retrieve the housing bolts and install them in a clockwise direction around the engine.
The switch is located behind the glove box and you will need at least a phillips screwdriver to replace the switch. Remove the glove box and the switch should be right there, Replace the switch.
The switch is located directly on the back of the fan housing. You slide the prong off, and slide the new one back in place. Make sure the car is off and hasn't been running, you don't want to chance your hand in the fan.
If its just the switch panel that has gone bad and you know for sure that is whats wrong, go to Ebay motors or your local salvage yard to get a replacement for cheap.
Not easy job, take off the blower housing then put bolts in safe place. The wires will have to be removed in order to put them all each on at a time. After the new wires are on, then take mounting switch off and put the new one in.