Hello! I have a can of 134a refriderant and when I looked for the A/C low pressure port for my '03 Nissan Altima, I found a valve 1 & 2 on the left upper/back part of engine, and an unmarked tube on the upper back part of the engine. I cannot locate this port in my Owners Manual and need to get this done today. Where do I find this A/C low pressure port?

On top of AC Accumulator

Leave A/C work to the trained professional
Most likely is empty & need to have a leak repaired
& then vacuumed,before charging
You can't do that & those store bought hose things are
junk. Need knowledge to work on any refrigerant system

Problems with Nissan 2005 Altima include-Crank shaft position sensor with ECU reset, ECU Factory reset from Dealer, Low Fuel pressure requiring fuel pump replacement, Replacement of ignition coils causing misfire during start-Catalytic Converter Recall-Oxygen sensor on exhaust-Leaking Valve cover gasket-Radiator failure due to plastic top & Bottom (Constantly adding water to reservoir?)

On the low pressure valve located between the compressor and accumulator. The low pressure port has a black or blue cap covering the recharge valve. Don't worry, you can't connect the hose to any other valve port but the low side, the hose end is different from the high side. The high side has a red cap, and is not a recharge port.

The low pressure lines are larger. Follow the larger line from the compressor to find the low pressure port.

hmm ..if you are looking for the low side air conditioner port .. then locate the condenser (thats in front of and looks like the radiator) .. you will notice two tubes going to that ..one is large the other small .. the small tube is the high pressure side .. the large tube is the low pressure side ... follow the large tube back until you find a cap that covers the low pressure port .. thats where you would fill with new refregerant (r134a) .. if you buy r134a, you can also get a filler hose and gage.. that hose will only hook up to the low pressure port ..it wont fit the high pressure port ...

On my 99 3.8L it was coming right of compressor. The low side is the bigger diameter hose & tubing of the 2 lines. Follow the bigger line from compressor, and look for a plastic cap on valve.

look near the radiator follow the line from the reciever dryer till you find it, on some they put the low side on the compresor line near the compressor, and some way low by the radiator.

AC ports caps are most offen blue in color, they have either a H (hi pressure) or L (low pressure) on the top. You want the one marked L

Down low between the radiator and the engine. Look for the cap. Very hard to reach without burning your hand if the engine is hot. I had to rig a much longer hose to add 134a so the can would be upright while putting it in.