4 - high pressure; 5 - a low-pressure side; 6 - low-pressure side.
The air-conditioning system with R-134a refrigerant ports are available with the "quick-connected" adapters. Each adapter is a sleeve with an internal thread for protection against ingress of contaminants.
PERFORMANCE ORDER
1. Close both valves on the highway.
2. Connect the adapter to the appropriate pressure gauge ports.