Service Port HVAC: Description and Operation
Two refrigerant system service ports are used to charge/recover/recycle/evacuate and test the air conditioning refrigerant system. Unique service port coupler sizes are used on the R-134a system to ensure the refrigerant system is not accidentally contaminated with R-12 refrigerant or refrigerant system service equipment.A/C System Service Ports - Typical:
The high side service port is located on the receiver/drier. The low side service port is located on the suction line, near the right strut tower. Both the high side and low side A/C service port valve cores are serviceable.
Each of the service ports has a threaded plastic protective cap installed over it from the factory. After servicing the refrigerant system, always reinstall both of the service port caps.