A/C low side port location - photo would be helpful

The low side valve is located on the suction line near the A/C compressor. The low side A/C service port valve core is a serviceable item. The high side A/C service port valve core is located on the liquid line fitting attached to the top of the receiver/drier. The high side A/C service port valve core is not a separate serviceable item. If the high side service port valve core is faulty or damaged, the front section of the liquid line will require replacement.