Hello I will help you with your question,
The low pressure port is located between the Evaporator under the dash and the compressor mounted on the engine. It is in the low pressure line which is the larger of the two lines.
If you will tell me the Year, Make and model of your vehicle I may be able to provide a diagram or at least narrow it down for you
Thank you
Yes they hid the port on that one as the compressor is at the bottom of the engine,
The service information lists the port as being on the manifold lines at the compressor
I just found this diagram showing the port on the manifold at the compressor
Let me know how I can help you with this
ASE Master Technician
ASE Master Tech 10+ yrs, AAS Automotive Technology, Factory trained Asian specialist