1999 Jeep Cherokee electric fan

welcome to the forum, there should be a fan relay in the power distribution center. Pulling the relay should kill the fan? If you have a digital multimeter or led testlite, you can check voltage circuit at the relay. Voltage to load side of relay is hot all the time. Voltage to coil side of relay, goes hot with the key on, That circuit should not be hot with the key off. Also, the pcm controls the coil ground in order to energize the relay.