Automatic Temp/ Heat works no A/C

rule 1 . all cars. all electrics check the fuse in both boxes.
if it works on one vent , with full blow force, and full heat
its not the engine, the blower, or the heater temp path.
its the dampers
there are 3 technologies of dampers, cable, vacuum and motors.
some are hyrbid. mixed.
The FSM covers this. grand or not grand cherokee, big diffr that.
ill guess. your posted to grand but its a non grand so will answer for
plain jane cherokee.
i log in to alldata.com so can you!
oops yours is the VACUUM monster, and with blend door feedback
electronics. did you scan the PCM to see if it has DTCs for HVAC fails?
my online source has poor Hvac, docs. zero vacuum side. so....
FSM time.

So with all vacuum systems. the control failed to send the vacuum out to damper solenoid
the hose fell off, or is cracked.
the servo is dead, or has cracked diaphram
the damper rod fell off
the damper is jammed.
what i do with all vacuum servos; is move it by hand, got heat now>?
bingo, job half solve in 5 min work.
yes i reach up there or remove glove box, what ever it TAKES.
to touch the slave servo.

happy new year !

The blend door is in the HVAC box located under the dash on the passenger side. A faulty electric door actuator is often the cause of this - there is a really good video on YouTube showing location and how to replace it.

I really can't be sure off hand, but what you wrote looks like the control valves are sticking(these flaps allow air to go different directions at the vents). its located at the heater core(towards the left side of the heater core) under the plastic just under the dash. you can manually move them, encase they are stuck, they do stick sometimes. while checking the vent doors, make sure your vacuum lines are connected. also check to make sure your vent hoses are tight. I hope this helps

Yes, The driver side actuator has failed, actuator is mounted on passenger side of heater case under the dash, remove close out panel on bottom of dash, remove glove box then turn on key actuate the temp control switches and watch for movement of door linkage and you can tell which actuator isn't moving.

the motor for the passenger side
blend door is shot

need passenger side temp door actuator prob dealer only part will need to remove glove box door will be two actuators, its the one behind the dash frame not the easy one to get to will have to disconnect battery after replacement and not touch hvac controls for it to recalibrate fow a few min

There are,what they call vent door actuator motors that open,and close the vents on each side these go bad time to time.If the glove box is getting hot,the heater control valve could be another problem also.First thing to try is,behind the glove box is a vacuum junction with a threaded stud(very small).There is a nut that holds the vacuum plug to the junction.It is on the stud.Unscrew it(it is time consuming).Then gentley,remove the plug.There will be little **** that align with the vacuum plug that could come apart,so be carefull.Use a silicone spray,and nothing else,and spray in the junction,and the plug real good,and replace the vacuum plug back as soon as you can.Do this as the ac is on and engine is running,so it will **** the lubrication in where it is needed.If it is a vacuum switch is stuck,this will make it start working again.Then ,if everything (vents and cool air)starts working,check the heater control valve to see if it is opening,and closing.The heater control valve closes off the hot water from entering the heater core,therefore,keeping the temp,in the air box from heating up.If I can help,let me know.

It sound's like one of two thing's, first open the glove compartment look behind to the left you will see a clear vacuum line going to a goldish in color accuator remove it once the vehicle is at normal operating temp. if you get heat then you have a problem with the vacuum switch, just plug the vacuum hose, you will have to reconnect it in the summer to get the AC working. The other problem could be the heater control valve, located under the hood inline on the hoses going to the heater core, upper passenger side of the fire wall.

There is a blend air actuator on the passenger side that causes the blend air door to stay open to heat no matter what. It's below the left side of glove box, facing dash, and you can work it by hand and get it to close. If that works, get a new one. They're very easy to install.

sounds like the drivers temp door actuator is not working should be located on the drivers side of the air box down by the gas pedal or center dash area