Where is low side valve on 98 lumina?

On a 1998 Chevrolet Lumina, the low side service valve for the air conditioning system is typically located on the larger diameter aluminum tubing that runs from the evaporator to the compressor. It is usually found near the firewall on the passenger side of the engine bay. The valve is often covered with a plastic cap, and it is important to identify it correctly to avoid servicing the high side valve by mistake.