Easy fix for broken blend doors on the WJ with AZC (automatic zone control) without removing the dash. I only needed to remove 2 screws!!!!!!!!!
My 2001 WJ passenger side was not producing heat, diagnostic code was 56, “right temperature door travel too large.” This told me the actuator was rotating but not the blend door. O, sh@#!!!! I know what this could mean.
The Jeep dealer wanted $1200 to remove the dash to fix the broken blend door, replace other parts that are not broken and I would have loss of vehicle use for 2 days. To do the job myself, remove the dash and make the repair would cost $132 for the blend door sub-assembly, $100 for a R134 recharge and 8-12 hours of my time and loss of vehicle use for 2 days. Both of these options were nuts and winter was approaching.
Removing the dash to replace a blend door is like holding onto a light bulb and then having your home rotated to unscrew the bulb. Some creativity was needed here.
I studied the pictures in my service manual and decided to go where no one has yet gone, “open HVAC blend door surgery.” All I had to remove was the glove compartment door and the driver blend door actuator (motor.) Can you believe that, only 2 screws? Next I used a 2.5” diameter hole-saw and carefully cut an access/inspection hole into the HVAC housing to the right of the driver blend door actuator motor in a large open flat area between the heater core and evaporator core.
“There they were,” the blend doors, and I did not have to remove the dash. No stopping me now as I enlarged the opening with a hacksaw blade. The plastic HVAC housing cuts very easy, so I cut cautiously so I would not damage the heater or evaporator cores or I would be removing the dash. I made the opening only large enough to allow hand access. Next I turned on the climate control and adjusted the driver and passenger controls and watched the driver blend door functioning properly, the passenger blend door was not moving. I then reached in and easily lifted out the broken blend door, saying to myself 30 minutes after I started, “why is this so easy.”
There are two directions you can go from here.
The no-cost direction that got me through the cold is to fabricate a removable panel and position it in the up position, where the blend door would be for heat only or in the down position for cold. For my 2001 WJ, the panel was 4.5” x 4.25” with a notch in the lower corner to clear the door pivot shaft bushing and made from .010” think aluminum. The panel is slightly oversize for the cavity it fits into so it locks into place. I also attached a handle, something as simple as a drawer knob or 2” screw with a nut, onto the panel to make it easier to install and remove as climate changed. Finally I fabricated a panel to cover the access hole I cut into the HVAC housing. For this I also used .010” thick aluminum. I attached thin foam strips around the perimeter of the panel to make a seal against the HVAC housing. “This is almost too easy.”
The second direction and complete fix required the purchase of the blend door sub-assembly, yep, I had to spend $132, and use only the blend door from the sub-assembly. I started by prying out the driver side white plastic door pivot shaft bushing to release the driver side blend door from the sub-assembly. I studied how the door pivot shaft bushings are held into the blend door sub-assembly as this helped me later. Next I removed the passenger blend door by rotating the blend door to the almost upright position and then sliding it away from its door pivot shaft bushings. I then re-installed and removed the blend door from the sub-assembly as practice at this helped me later.
Driver side blend door fix.
The driver blend door has to be removed to replace the passenger blend door. This is the blend door closest to the opening I cut in the HVAC housing. After glove box and blend door actuator removal, pry/pull out the white, door pivot shaft bushing, remove the broken blend door, drop in the new blend door, press the new or old bushing back in with the bushing stop tab oriented correctly by aligning the grooves in the bushing with those in the door, re-install the blend door actuator and your done. The blend door actuator motor had rotated before I realigned it with the white bushing. By applying 12 volts to the blend door actuator connector pins the keys on the blend door actuator output door shaft realigned to the mating keys on the white door pivot shaft bushings. I then fabricated an HVAC cover as described previously. Total cost and time to fix the broken driver blend door is $132 and 1-2 hours. Could it be any simpler?
Passenger side blend door fix.
The passenger blend door was a little more difficult to replace but can be done. There is a partition wall between the two blend doors that needs to be partially removed and replaced later. Removal requires the use of the hacksaw blade. I made a horizontal cut, right to left. This cut is critical, the piece removed needs to be put back in place and secure the blend door center pivot. After glove box and blend door actuator removal, I removed the drivers door pivot shaft bushing, then the drivers blend door, the patrician as described above and finally the broken passenger blend door pieces.
I then placed the new passenger blend door in its position. Before doing so, I noted the position of the grooves on the door pivot shaft bushing. They were rotated out of position and I had to realign by turning on the AZC and hope the motor stopped in the right position, approximately 1-2 o’clock, it did. Alternately I could have run the calibration. It was a good idea to play with the blend doors in the blend door sub-assembly I purchased to get a feel for how the blend doors have to align with the door pivot shaft bushing and how they fit together. I positioned the new blend door onto the door pivot shaft bushing and applied enough pressure for the blend door to slide into place. This was a little tricky as I did not want to break anything. I put the piece of partition back in place and secured it with adhesive backed aluminum tape. Finally I replaced the drivers blend door, door pivot shaft bushing and blend door actuator motor. Before covering the HVAC opening I turned on the AZC, adjusted the temperature controls and watched those happy blend doors open and close. Wow, I am done, a passenger blend door replacement in 2+ hours.
If there is sufficient interest in this easy blend door fix I could make cutting templates, cover panel, and small piece of aluminum tape available. This could save you considerable time. Cost of these parts would be based on the demand and interest I receive.
Disclaimer: The above repair is done at your own risk. You should be mechanically inclined. Be aware of the dangers of your vehicle airbags and power system. Take proper safety precautions as outlined in your Service Manual.
Towvehicle (see notes below)
Below are additional tips if you wish to attempt this easy blend door fix yourself.
The passenger side door pivot shaft bushing or actuator motor cannot be removed for replacement with the above surgery, at least not yet. I am working on a solution for their replacement. You can actually touch the passenger blend door actuator motor by using the secret passage way. More on this later.
You may have to calibrate the door actuators to get the blend doors moving. Turn ignition on, set AZC to automatic, turn ignition off, remove IOD fuse, wait a few seconds, install IOD fuse, turn ignition on. Do not touch any controls for 60 seconds while the thing calibrates itself.
See the service manual for directions on removing the glove box, it’s a little tricky.
This blend door fix is not limited to a 2001 WJ with AZC, should easily work on 1999-2004.
With this blend door repair method you can do a little at a time and continue using your vehicle.
When the blend door breaks a second time (do they ever), repair is so easy now that you have the access panel installed and ready to open and replace the blend door. If the stop tab was broken from the passenger door pivot shaft bushing (which can not be replaced at this time) the blend door may have a reduced life.
Don’t bother trying to epoxy a broken blend door back together, it won’t last.
It is important to cut the 2.5” diameter hole first as this will allow you to watch the hack-saw blade and make sure it does not damage the heater or evaporator cores. When changing direction of the cut with the hack-saw blade you will need to drill a series of small 1/8” holes in line to allow you to force the blade thru to start the cut.