if you are referring to the a/c lines just trace the biggest line from the back of your compressor to the fitting and that's your low side port.
LOCATE THE SERVICE FITTINGS Next, you need to locate the service fittings on the A/C system. There are two: a LOW side fitting and a HIGH side fitting. The LOW side fitting is usually located on the suction hose or line that goes from the accumulator to the compressor. The HIGH side fitting is located on the line that goes from the compressor to the condenser. R12 Low Side 7/16 in. threaded ß----------à R134 Low Side 13mm Quick-disconnect R12 High Side 3/8 in. threaded ß----------à R134A High Side 16mm Quick-disconnect On older R12 systems, the LOW and HIGH pressure service fittings are screw-type Schrader valves. On newer R134a systems, the LOW and HIGH side service fittings are quick-connect style fittings. The LOW pressure fitting is SMALLER than the HIGH pressure fitting.
LOCATE THE SERVICE FITTINGS Next, you need to locate the service fittings on the A/C system. There are two: a LOW side fitting and a HIGH side fitting. The LOW side fitting is usually located on the suction hose or line that goes from the accumulator to the compressor. The HIGH side fitting is located on the line that goes from the compressor to the condenser. R12 Low Side 7/16 in. threaded ß----------à R134 Low Side 13mm Quick-disconnect R12 High Side 3/8 in. threaded ß----------à R134A High Side 16mm Quick-disconnect On older R12 systems, the LOW and HIGH pressure service fittings are screw-type Schrader valves. On newer R134a systems, the LOW and HIGH side service fittings are quick-connect style fittings. The LOW pressure fitting is SMALLER than the HIGH pressure fitting.
The A/C low side service port is by the Firewall, just below the Passenger's Side Windshield Wiper Arm.....
HHo it
The low side fitting for the air conditioner on a 1988 Chrysler LeBaron is located on the accumulator, which is typically found near the firewall on the passenger side of the engine compartment. It is a service port that allows for refrigerant to be added or removed from the A/C system. The fitting is usually smaller in size compared to the high side fitting, which makes it easier to identify.
The low side service fitting is located near the right side of the strut tower (inner) near the fire wall. It is located on the upper a/c metal/rubber hose. The high side fitting is located on the lower a/c refrigerent line to the left side of the right strut tower. Hope this helps
The low side (smaller fitting).
low side of a/c is the larger diameter line it the smaller fitting(charge side) vs. high side is your smaller line larger fitting
The low side has a bigger fitting then the hide side
The low side will be located on the front side of the a/c manifold..........
You did not give the year so I will assume a newer one. The low side fitting is normally on the accumulator. If your system has R134A refrigerant do not use any that has stop leak in it. That will ruin a shops equipment.
On a 1993 Mazda MPV, the low side recharge fitting for the air conditioning system is typically located near the accumulator or receiver-drier, which is usually found on the passenger side of the engine bay. It can be identified by its larger diameter compared to the high side fitting. Look for a service port with a plastic cap that may be blue or black. Always ensure the engine is off and the system is not under pressure before attempting to recharge.