A/C line to compressor. How do I put in 134a fluid?

davis, first off, this is to verify that your system uses 134a refigerant "The two refrigerant system service ports are used to charge, recover/recycle, evacuate, and test the air conditioning refrigerant system. Unique service port coupler sizes are used on the R-134a system, to ensure that the refrigerant system is not accidentally contaminated by the use of the wrong refrigerant (R-12), or refrigerant system service equipment." and looking at the description for the low pressure service port "The low pressure service port is located on the suction refrigerant line, near the accumulator. The high pressure service port is located on the liquid line at the passenger side of the engine compartment, near the condenser. Each of the service ports has a threaded plastic protective cap installed over it from the factory. After servicing the refrigerant system, always reinstall both of the service port caps." It does look like a standard port, and check the attached image to make sure you are trying to attach the refill to the right port. Please remember that you can not just vent this stuff into the atmosphere and that the A/C work should be left to a trained and licensed professional. Hope this helps, good luck.