97 jeep grand Cherokee wont blow hot or cold air on any setting and the blower motor is fine

There are two systems to evaluate.

1. Air Blows Fine but not Hot -> Check Thermostat and coolant level.
2. No Air Blows -> Check Blower Motor, Blower Motor Resistor Pack and Blower Control in Dash

Jeep Grand Cherokee is notorious for broken blend-air doors. This is the door inside the A/C-heater housing that switches the air from hot to cold. You must remove the dash to repair it.

Your heater core could be plugged with dust if this problem came up slowly I would suspect that. Another thing that cold be wrong is a trap door is not opening these are operated by cables vacuum or stepper motors. Confirm that something happens when you move from cold to hot on the control.

Make sure the compressor is engaged an running,and the dryer is cold,if so,then the temp door actuator motor is not working,it is in the dash mounted on the blower box,the dash will have to be pulled out toward the seats to replace the actuator motor

Probably broken blend doors if everything else is working, but its just blowing cold air. Do a google search for "Jeep Blend Doors" or "Heater treater" for more info.

Sounds like you need a blower motor resistor located down under dash on pass side next to blower motor. This is a comon problem and I have changed many of them. thats just the fan speed problem. Ive seen the blend doors break easily on those jeeps. thats inside the heaer core box and moves the flap from hot air to cold air. If it is stuck halfway -or mostly to cold- you may only get luke warm air. If they had the heater core out-maybe they possibly broke it.

try recharging the ac

this sounds like the recirculation door in the heater box is broken and this is a difficult and can be an expensive repair as the dash has to be removed for access. a quick check for this is if you release the glove box and let it hang you will see the heater box if you reach up to the left top you will feel a grid and the recirc flap is housed there you can operate the blower and hot and cold and see if flap moves

It's possible you are not getting enough coolant flow to your heater core. Try pulling the hoses off the core, blowing it out with air compressor, fill with water and blow out again. Try this about five times and see what happens. Alot of times these cores will plug up or have restricted flow. They will blow warm at low speed but it won't flow enough hot coolant through to stay hot on high blower speed.

Your blower motor could be "clogged" but I never saw one with enough debris in there to actually make one stop/ The cure for both is to remove the blower motor from the air box. if you find tons of leaves in there, clean them out. If the shaft on the motor has lots of side play, or will not run when connected hot to battery, replace it.