Where do I refill or recharge the R134-a refrigerant in my 2000 GMC Jimmy?

[Jennifer D]

Please look at the pictures I've posted. I'm trying to recharge the refrigerant in my 2000 GMC Jimmy SLE, but I'm not sure which port to connect the nozzle on the can to. The nozzle does not fit on the port connected to the skinny metal tube, but does seem to fit on the port connected to the cylindrical metal thing. However, the back of the can says to connect the tube to the Lower Port Valve...If anyone here knows, please let me know. Thanks!

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