Where Is the A/C Service Port in the Grand Cherokee?by Richard Ristow
A Jeep Grand Cherokee features two air-conditioning service ports. Both are located on Cherokee's aluminum air-conditioning pipes, which can be found centrally in the Grand Cherokee's engine compartment.
Finding the Ports
Pop the Jeep Grand Cherokee's hood. Find the air-conditioning system's aluminum pipes. Look for a stretch of pipe connecting the Cherokee's compressor with the drier. This is the location for the low-side pressure connector. The remaining service port is the high-side pressure connector. Both ports will be capped.
The Low-Side Port
The low-side port is prefigured to fit Freon recharging kits. The Cherokee takes either R12 or R134a Freon, but the system is only intended for one or the other. Adding R12 to an R134a system causes damage to the air conditioner. R12 is used in vehicles predating 1984. Vehicles manufactured 1984 and later are required to use R134a.
The High-Side Port
The Jeep Grand Cherokee's air conditioner is a pressurized system. This pressure helps move air through the metal tubes and the system as a whole. The high-side service port is intended for maintaining and adjusting the systems pressure. Freon recharging kits do not fit this service port. Attempting to add R12 or R134a through this port damages the air conditioner.