Jeep Grand Cherokee Dual Zone AC Repair

Image Jeep Grand Cherokee Dual Zone AC Repair
By Dennis Bandy Copyright
 
Some common AC problems with Jeep Grand Cherokee 1999 and Up
 
1. Blows hot on drivers side with AC on.
2. Blows hot on passengers side with AC on.
3. Blows cold on drivers side with heat on.
4. Blows cold on passengers side with heat on.
5. Hear blower but no air blows through any vents.
6. Airflow is present but it is not blowing cold.
 
Basics - Verify Correct Amount of Refrigerant
First check pressures on low and high side with an AC gauge set to help insure that the system is fully charged. If unsure what the gauge readings should be, see our related auto repair blog for help in interpreting the readings. Dual zone systems in particular, when the refrigerant is low may blow cold on the right side since it is closer to the evaporator and not as cold on the driver's side. If there is any doubt, recover the refrigerant with an AC machine then evacuate and recharge the system with the correct amount of refrigerant and recheck. The suction line should be cold and the discharge line should be hot, infrared thermometers are great for checking the temperatures without getting burned.
 
Incorrect Airflow or Temperature
Jeep Grand Cherokees with dual climate control (for the AC / Heater system) that have incorrect air temperature blowing on either the passenger or driver's side is usually one of two things. One of the blend door actuators (motors), or the the dual zone blend door assembly could have a broken door. The actuator that controls the drivers side is directly behind the glove box. The glove box is easily removed to access the actuator for the drivers side. Testing to see if the door is broken is simple to after removing this actuator, just turn the shaft manually (white piece in photo) to adjust the hot and cold for the driver's side vents. See our other article on an easier stronger repair kit to fix these HVAC doors for the Jeep Grand Cherokee.

More on Actuators and Doors
If the door is broken, the shaft will free-spin and the temperature will not adjust. The passenger side is more difficult since the actuator is located on the HVAC case on the firewall side. Since this is much harder to get to, it does require removing the dash and then the AC/Heater case to remove and replace the actuator and or dual zone blend door assembly. If the fan blower can be heard but there is no air blowing through any of the vents it is most likely that the recirculate door has stress cracked and is broken. The recirculate door can break and fall covering up the blower opening, restricting all air flow.
 
Q: On my 01' Jeep Grand Cherokee...when I turn my vehicle off, after about 30-50 seconds that door makes a constant clicking noise for about two minutes then stops! What would be the component that needs to be replaced in that situation? I took the fan out an looked at it while it was going at it and the door goes up...then clicks for a bit...then drops back down center...then does it again. It does eventually stop within 1-2 minutes or so.
 
A: The clicking noise you are describing is usually one of the actuators (electric motors) that operates one of the doors that directs the airflow in the evaporator/heater case. Actuators can make this clicking noise if one of the plastic gears is broken. The door can also make this noise if it is cracked where it attaches to the actuator. Some of the actuators are difficult to access and may require removal of the dash. If you can access the actuator try unplugging it and see if the the clicking stops. This will verify you are looking in the right area. Then remove the actuator and verify the door opens and closes by hand and that the door is not cracked or broken. In most cases with this sound it turns out to be an actuator. The dealer is your best bet for finding a replacement part. Use the numbers off the old one since even the dealer has a difficult time looking up the correct part when it comes to actuators.
 
AC Water on Floor Board
If the evaporator drain gets clogged, excessive condensation can build up on the outside of the evaporator case and then drip to the floor. Try clearing the drain with compressed air (using a wire can cause damage unless very careful). You may see quite a bit of water rush out, if the drain was clogged. After clearing the drain run for awhile with the AC on and verify water is dripping out of the drain normally. Another cause of a soaked carpet could be the donut seal that goes around the AC drain. If this seal is compressed too much it may allow the water to enter the passenger compartment. Replacement of the seal or adding on a drain tube extension (rubber hose) will prevent the drain water from leaking on the firewall and running in the vehicle.
 
Typical Jeep Grand Cherokee Evaporator Case Removal
1. Disconnect battery. Remove the refrigerant using an AC machine. Remove the heater hoses and ac lines at the firewall. The spring lock ac line connectors can be disconnected easily with a spring lock tool. Remove the 10 mm bolt near the heater hoses in engine compartment that goes through the firewall to the evaporator case.
2. Remove the center console, look for hidden screws inside the rear of the console with the cup holder slid open. Remove shifter assembly, place the nylon strap to the side.
3. Use a trim tool to remove both pillar trim pieces and dash trim panel near windshield, pry the defrost vents from the dash panel (just loosen them do not remove). Remove the bolts along the top of the dash panel near the windshield.
4.Pull the weather stripping and place out of the way. Use trim tool to remove panels in bottom door opening, remove screws that are now revealed that secure kick panels and remove kick panels.
5. Remove both trim pieces from around glove box, remove the 10 mm bolts that are now revealed that secure dash panel.
6. Remove the bolts that hold the dash panel on each end. Remove the hidden 13 mm nut that is straight up, it is located to the right of the brake pedal - look straight up.
7. Remove the trim underneath the steering column, allow the steering column to rest on the drivers seat.
8. Unplug electrical connectors on driver and passenger sides. When the dash is slowly pulled back look for any missed electrical plugs that may still be attached.
9. The passenger side may have a plastic retainer built in that held the dash during assembly, pry the retainer to allow dash removal. With a helper swing the passenger side of the dash and bungee to passenger seat.
10. Remove evaporator case attaching bolts and remove the entire evaporator case from the vehicle. Now the evaporator, dual zone door assembly or rear actuator can easily be serviced.
11. To complete the job reverse removal instructions. Refill coolant, evacuate and recharge the ac system.
 
Reader's Comment

Hey Dennis,

I really like the article on how to get at the blend doors on a Jeep Grand Cherokee. Have you done this personally? It looks do-able but I just came from the dealer that said he has two JGCs that were towed in 'cause owner could not complete the R&R. I thought I should check and see what your success rate is on your described proccess. Thanks

My Response
 
Thanks for the comment. Yes, I have done many of these (probably forty to fifty). I wouldn't recommend someone that doesn't have previous dash work experience to do this as their first big job; especially without having a tech that's done one before helping to guide them through it.
 
I once had to take the HVAC case back out after replacing just an actuator. In haste I missed the broken blend door assembly, it was the first broken one that I ran across. The first evaporator core I replaced in a Jeep Grand Cherokee (basically the same job) took about 8 hours. After I did a few though, I could have the dash swung and the HVAC case out in about 30 minutes. I would have it completed in about an hour and fifteen minutes.
 
As far as success rate, I haven't had anyone respond one way or the other. My thought is that if someone is confident in their own mechanical abilities (ie auto technicians) this will give them enough information to decide if they will proceed with the repair.

Readers Question on Jeep heater.
 
I have 2000 Jeep Grand Cherokee Limited, I get heat on the drivers side and cold air on the passenger side, it has the dual controls, so I need to know what part I need so I can fix it without taking the dash apart. Can you tell me what part I need?
 
My answer on Jeep aftermarket parts.
 

On the Internet, there are some aftermarket heater/air conditioning blend doors available for do-it yourselfers. Replacement heater door parts (Jeep parts advertisements) appear on our webpages from time to time on the Google ads. My understanding is that heater doors can be installed in the vehicle without dash removal. Also they convert dual zone doors into a single zone, which isn't a big deal for a lot of people. On their description, the product listing says "no discharging the ac is required, no draining coolant and no dash removal is needed." Since the ebay replacement heater blend doors, actually alter the original design, most professional auto repair shops wouldn't be likely to use it, unless the customer understands and agrees to the change in function.

Jeep Grand Cherokees problems with dual heat and air conditioning controls may give you cold feet or make you hot under the collar.