Low ac port location on 2000 buick century

found the low pressure port (blue cap) near the bottom of the radiator, almost directly below the high pressure port (red cap) directly behind the radiator.

General info

https://anewwayforward.org/ac-low-pressure-switch-location/

Under the air filter box

https://www.google.com/search?q=2002+buick+century+low+pressure+ac+switch+location

..

There are 2 capped ports the low and high sides. The freon gauge set will only fit on one of the two ports. The low side. Run the ac attach the freon hose and add as necessary

I’m happy to help further over the phone at https://www.6ya.com/expert/david_66a56a0239b6ab32

The low which is the one you charge your A/C
with is located on the rear firewall about dead center 5approx 5 inches below the windshield. Make sure when charging you put your a/c on coldest setting and blower on high.
Hope this helps
God blessss

i believe on that model it is on the receiver dryer the tin can looking part

before chasing doors inside the heater box a low freon charge will cause the problem your looking to repair

1998 Buick Century is factory-equipped with R134a refrigerent.

As for the service port, you just have to look for it. Not even the factory service manual will tell you exactly where it is located. It will be either on the accumulator itself or in the low pressure line between the accumulator and the compressor. (see diagram)

You shouldn't be working on Air Conditioning

You obviously have no knowledge or training

Take it to a repair shop ,so you don't do more
harm than good & you will, if you try to add refrigerant
only to have it leak out & polute the atmosphere

In the low side ac port.Follow ac lines until you find a part with a black cap, there are 2. The big one is the high side and the smaller one is the low side.

it is located in the low side AC line from the AC compressor, the low side line is the larger of the 2 lines comming from the ac compressor on the passenger side front of the engine