There will be two. Generally the low pressure is mounted more towards the front of the car and will most likely have a blue cap on it.
If it does not have a blue cap on it compare it with the high pressure port. The high pressure port (for r134a) will be wider with different threads where as the low pressure port will be slim.
If you cannot find either search deeper with a flash light. Be careful to wait till the car has cooled, although you should not have to search too much as the low pressure port is generally easy to reach.
Also, check the label on your car to make sure it is r134a coolant. If it says r12 you will need to take it in to have it charged with r12.
standing in front of the car, the low pressure port is on right hand side near the fuse box. the high pressure port is on the left hand side near the windshield washer fluid tank.
The low pressure port is located on the left side of the car towards the back of the engine compartment. It was a blue cap on it with a capital L.
look for the port with the black cap on it, it's the low pressure port.
low pressure towards the evaporator ( towards the inside of car) and the high pressure is towards the condensor in front of the radiator
On the evaparotor (black canister) on passenger side
On the ac system, the low pressure port is the smaller port. It will be located on the line coming from the dryer. The low pressure line is the larger line. it will be on it.
low pressure port is on top of the ac compressor
The low pressure freon port is located on the low pressure line that is attach to the ac compressor (driver side). Safely jack up the car, look underneath at the compressor, then located the low pressure line (larger diameter). There you'll find the port underneath a cap.
the low pressure port is right on top of the comperssor
The 1997 Volvo 850 low pressure port is located on the air conditioning compressor. The low pressure port will be on the right hand side of the compressor.
the low pressure port is located on the back side of AC pump. you have to jack the car up a bit to get to it under the car. you will see the BLUE cap on the back side or the under side ?
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.