Start a camp fire with your Chilton/Haynes manual. If you are going to do any serious service work on your Cherokee, you should own a Factory Service Manual.
97-01 the coolant temp sensor is on the thermostat housing.
That's indicative of everything cooling related, such as water pump, loose belt, crud in the coolant, etcNORMAL presentation of a weak/failing manual clutch fan is overheating in the drive-through/at a stop light/stop and go traffic, then when you kick up the RPMs the fan will manage to move enough air to cool things back down.