I need to hook up my refrigeration manifold gauges to the low side port.

I'm trying to find the low side Air Conditioner port on a 2002 Pontiac Montana so I can hook up some refrigeration manifold gauges. So far I can only see one fitting which seems likely to be an Air Conditioner port and it is a few inches from the reservoir for the refrigerant. Given its position I'm thinking it is not the low side port... can anyone tell me exactly where to find the low
side port?

Although I do not know he exact location of the low side service port on that model I can tell you that it will be in the refrigerant line between the compressor and the evaporator. Seems like it would be easy enough to just start at the compressor and follow the line back towards the firewall
until you find it. The low side line is larger diameter than the high side so you can't get them confused. The service ports are also different sizes so the blue low pressure hose with your refrigeration manifold gauges will only fit on the low side fitting.