I am trying to locate the low pressure a/c port on my 91 lumina to add r134a can anyone tell me where it is?

Good Day! I hope you're enjoying a pleasant one. I have a '90 Lumina Euro Coupe with the 3.1/V6...... my ports are located on the left/drivers side towards the air cleaner housing & battery, under the air cleaner housing to throttle body duct hose, between the cruise control solenoid and the battery...... the Accumulator/Drier is located under the air cleaner housing mount in front/next to the battery.......