The compressor in your Jeep Cherokee air conditioning system drives refrigerant through the A/C system and pressurizes the refrigerant gas so it can absorb heat energy. The compressor has a clutch mechanism that allows it to kick in and out, depending on the temperature in the passenger compartment. It has a belt drive and either a single belt or serpentine belt, depending on the year and engine in your Cherokee. There is a high-pressure hose that pushes refrigerant to the evaporator housing and a low-pressure side that returns refrigerant from the condenser.
Take your Jeep Cherokee into a professional A/C shop to have the refrigerant drained before attempting this repair. Never drain the system yourself. Once drained, the compressor hoses may be safely disconnected.
Disconnect the negative battery cable with a box wrench. Disconnect the compressor clutch electrical connection at the compressor by pulling apart the two sides.
Remove the compressor drive belt. Start by loosening the compressor pivot and adjustment bolts with a wrench. Pry the compressor away from the engine with a pry bar if necessary. Remove the belt from the compressor drive wheel.
Disconnect the high- and low-pressure refrigerant hoses from the compressor with two wrenches to keep the hoses from twisting.
Use electrical tape and plastic bags to close off the ends of the hoses and prevent contaminants from getting inside them.
Remove the compressor's attachment bolts with a wrench and remove it from the engine.
Bolt the new compressor in place with a wrench. The new unit will come with instructions on how to drain excess refrigerant oil before installing it. Replace all of the O-rings according to the instructions, lubricating them first with refrigerant oil.
Reattach the drive belt and measure the belt tension with the belt tension gauge before tightening the attachment bolts with the wrench. Belt spans of between 7 and 11 inches should have 1/4 inch of play, and spans of 12 to 16 inches should have 1/2 inch of play.
Reconnect the high- and low-pressure hoses to the compressor after removing the plastic bags and electrical tape. Use two open-end wrenches to prevent the hoses from twisting when tightened. Re-connect the compressor clutch electrical connector and reattach the negative battery cable with the wrench.
Take the vehicle back to the air conditioning shop and have them evacuate and recharge the refrigerant and test for leaks.
