Start looking at the compressor, specifically the bigger of the two lines that are connected there. That line is the low pressure line...follow it to the firewall, and somewhere in between the two points you'll find the service fitting. Remember, AC refrigerant is under high pressure, even with the AC off and the engine not running. When released, it's temperature drops well below freezing and can "freeze" you.
The 1991 VW Jetta low pressure port can be found on the air conditioning compressor. There are two ports, the low pressure port will be labeled as such.
The low pressure port is the one on the accumulator (the canister). The low pressure lines are the bigger lines and the high pressure are the small lines.
The low pressure side is located on the compressor. To locate the port, jack up the driver side and crawl underneath to locate the compressor. Add the freon to the port on the compressor.
The low pressure service port for the AC on a 1998 Olds Aurora is located on the side of the accumulator. It is at the back of the engine compartment, on the passenger side.
I believe that the computer data port or known as the ALDL is located behind the ashtray on a 82 Corvette.
It is the port on the aluminum line running right behind the radiator, near the radiator cap.
Larger hose from the air compressor
To add Freon locate the low-pressure port on the A/C system, also called the low-side service port. You will find this port against the firewall, at the back of the engine compartment.
The low side service port is located on the suction side hose going to the a/c accumulator on the passengers side right next to the strut tower......
Does anyone have a diagram for the Vacuum connections for a 1985 5.7 L Tune Port Injection Corvette engine?
It's the same hole as the headphones port.
behind the grill to the right of steering column