Simply ,the bigger of the 2 going into the out side/inside unit,and if running in summer,cold and sweating.
High side and low side refer to the pressure in the ac system. Ie The high side is the high pressure line and low side is the low pressure line.
The low side will be on the accumulator and the high side will be on the discharge line.....
The low pressure ac port is on the passenger side of the vehicle. It is close to the firewall mounted on the low side aluminum line.
The low side ac port is the line to charge in. the low side has a different size connection from the high side to prevent using the wrong port.
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 runs from the metering device outlet to the compressor inlet. Find your AC compressor. There'll be a small line connected to it, and a large line. Start following the large line. At some point, you'll come across the low side schrader valve. And there you have it.
The low side is always the big line on the a/c system. The little line is the high side.
the low pressure line will be the cold line if the ac is running or if you find the two ac coupler fittings, the smaller of the two is the low pressure side. typically has a blue cap or an L on the cap
The Low side line attaches to the compressor on the driver side of compressor. The charging port faced forward. The high pressure port faces up.
The one that is in the biggest line, You have a small line and a big line. The big line is the low side, and the small line is the high side.
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.
If your AC works and you can fell the metal lines with your hand, the high side is the line running to the radiator area of the truck first. It will be hot from the pressure. The cold line that is normally dripping with condensation is the low side at the fire wall, pasenger side.