It is the Toyota A/C condenser that cools the pressurized refrigerant it receives from the A/C compressor so it can be used to lower the temperature inside the passenger compartment. This air conditioning component can be found in front of the radiator in the grille section of your Toyota. The cooling process the A/C condenser performs is required for the HVAC system to operate properly. Most passengers in a vehicle have experienced the reduction in the air conditioning system's ability to provide cool air to the passenger compartment when the vehicle is stopped in traffic. This is caused by a reduced level of air flow over the air conditioning condenser. Because of this condition, the refrigerant is not cooled sufficiently to perform its task of cooling the system. Once the Toyota begins to move again and air flows over this air conditioning component, the HVAC system will again operate as it was designed to. The A/C condenser has no moving parts to it and cannot just fail. What affects the ability of this air conditioning component to function is if it is punctured by an object from the road, or if one of the O-rings that it is attached to the system with wears out. There is one other possibility of the A/C condenser becoming problematic on your Toyota and this is if it springs a leak from the inside. The purpose of the A/C dryer is to remove any moisture from the system. If it is saturated for any reason the moisture will combine with the refrigerant and creates an acid. This acid will eat away at your Toyota A/C condenser from the inside out causing it to leak. This will require it along with the A/C dryer to be replaced.