Where is the a c low side service port on a 2000 Pontiac Grand Prix GTP?

im not sure on the 2000 gtps but on my 98 gtp the low pressure service valve for the air conditioning in located in the very back of the engine compartment under the windshield.The high pressure is located on the driver side next to the fender. you can go to efproducts.com for informational videos on how to use their products to recharge your systems and retro fit the new valves if you need to.hope this helps.