AC fitting on the high side ? location?

Okay so my AC wasn't blowing cold so I took it to the dealer. They did the dye test and said "it was leaking around a fitting on the high side." The fitting was only $11 plus the labor, evac, and freon --- not bad. However, I forgot to ask the tech to show me the location of the fitting (o-ring?). I'm not sure when I look under the hood which side is the low side and which is the high side.

Does anyone know what/where this might be?

R12 or R134a?

The low-side fitting (sometimes has a blue cap) is usually on or near the accumulator, and the high-side fitting (physically larger and sometimes with a red cap) is usually, but not always, near the condensor at the front of the vehicle.