2007 Pontiac G5 ac low pressure service port?

I am want to check the pressure and if needed charge or boost my cars ac, does anyone know where the low pressure service port is? I found the high pressure port on the passenger side towards the firewall but when I follow all the lines connecting my ac system I cannot for the life of me find the low pressure...help please!

Took me a bit to find it, so I'm posting for others searching. It's under the engine cowling, to the right of the engine. Remove the oil cap to lift the cowling up, put the cowling aside, and replace the oil cap.