1971-73 Mustang Heater Blower Motor Resistor Female Plug - Original. This Heater Blower Motor Resistor Switch Plug came out of a 71 Mustang but is the same for all 71-73 Mustangs (without AC). Some of the wiring colors may be different if you have a 73 Mustang, but you can change your pins and put them into this plug. If your Heater Blower Motor Resistor Plug is damaged or missing, then this is for you!!!