The rear air conditioning system operates with the front system. The rear air conditioning system does not operate independently. You can control the rear blower motor speed even when the front system is turned off. The rear blower switch provides recirculated (inside) air to the rear compartment. Recirculated air is not refrigerated. Air enters the unit and passes through the evaporator core into the passenger compartment through the air distribution duct. The front system controls the rear system. A three-speed blower switch controls the rear overhead system.