Where is the low side service port on the AC line on a 2006 Buick LaCrosse?

On a 2006 Buick Lacrosse, the low side service port for the air conditioning system is located on the larger diameter aluminum line, typically near the firewall on the passenger side of the engine compartment. It is usually covered by a plastic cap and is identifiable by its smaller diameter compared to the high side port. To service the AC system, ensure the vehicle is off and the engine is cool before accessing this port.