On the coolant line behind the engine, it is a small valve, the larger one is the high side service port, before it goes into the cabin. If that was confusing, start at the engine block, look for a black line behind it that runs from the A/C to inside the car with two black capped valves, use the smaller one.
The 2001 Chevrolet Impala low side service port can be found on the top of the air conditioner compressor. The port will be labeled as the low pressure port.
The 2002 Chevy Cavalier low side service port can be found on the top of the air conditioner compressor. The low side service port will be labeled as the low pressure port.
The AC low side service port on a 1999 Chevy Astro van is located next to the firewall. It is the port that is closest to the evaporator.
The recharge port is on the larger AC pipe
On the accumulator.
Low side service port is against the firewall just underneath the alternator. It has a Blue cap on it.
back side of engine toward the fire wall.
The A/C low side service port is by the Firewall, just below the Passenger's Side Windshield Wiper Arm.....
Into the low side service port.
The service port is by the Firewall, just below the Passenger's Side Windshield Wiper Arm Shaft.....
If you are talking about the low side for the AC system. there should be 2 ports. The port that is on the largest diameter line is the low side.
Reach down between the alternator pulley and the firewall. The service port is down there. has a blue plastic cap on it.