The blower switch is the knob you turn on the heater control in the dashboard. If you are talking about the blower motor resistor, it is located in the passenger's foot well area, mounted in the heater box.
Most times the resistor is located on the side of the blower motor housing, located under the passenger side dashboard. On some cars,trucks, it is located on the passenger side on the firewall in the engine compartment.
The heater blower motor can be found beneath the passenger side dashboard. Remove the wiring harness from the back of the blower motor. Remove the blower motor retaining bolts. Reverse the process to install your new blower motor.