Where is the ac Freon low pressure fitting on a 1999 Lincoln Navigator?

On a 1999 Lincoln Navigator, the low-pressure fitting for the AC system is typically located on the larger diameter aluminum line that runs from the compressor to the evaporator. It can usually be found near the front of the engine compartment, near the passenger side. The fitting is often capped with a blue or black plastic cap, distinguishing it from the high-pressure fitting, which is usually smaller and located on the smaller line. Always ensure the engine is off and the system is not under pressure before attempting to check or service the AC system.