DIY Fix for Jeep Cherokee A/C Blend Door Failure

Like most DIYers I see a problem and the last thing I think about is "where do I take this to get it fixed?" I instead ‎look at a problem and try to outwit traditional solutions. That being said, when I didn't have heat in my Jeep Grand ‎Cherokee (JGC) during our first cold snap I naturally went online to diagnose and solve the problem. What I ‎discovered was this is a very common problem with my model of JGC (1999-2004). I love my Jeep, but the person that ‎designed this blend door actuator system needs to find new work. The design is inherently weak, and relies on a ‎calibration phase that puts intense pressure on the weakest points in the system. Not wanting to repair the faulty ‎design with the same OEM design, I set out to reverse engineer a long-term solution

This website was among the more helpful sites as it provides Jeep's Repair kit instruction.  Thanks for a well thought out site, and permission to borrow content.

http://www.denlorstools.com/autoblog/2010/03/jeep-grand-cherokee-dual-zone-blend-door-repair/

This site does a good job of where and how to cut, so I will not re-invent the wheel.  I'll show you my solution to the kit from Jeep.

Total Cost of Project:
$1.76  Mending plate ($0.88 x 2)
$3.36  Hinges ($1.18 x 2)

Required Materials / Tools:
4  - 1/8" rivets
1  - Rivet gun
hacksaw or rotary tool (the hacksaw requires more patience than I possess)
Drill

I was able to remove and manipulate the outside most blend door actuator, connector and door without any issue. I ‎could have fabricated all new parts reasonably easily, however the passenger side control would not have worked. ‎So I worked within the OEM connector parts to ensure dual climate control operation.
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I decided on a standard 3 inch door hinge as my new pivot point. This stamped steel piece should be more than ‎sufficient to withstand the calibration forces. The door is a reinforcing plate typically used on decks and truss ‎frame construction. These both will be very easy to find at your local home center. The truss plate is found in the ‎pressure treated section.‎  You will need 2 of each to complete both blend door repairs.

The concept of the repair is to rivet the truss plate to the hinge, manipulate the hinge barrel to work on the OEM connector, and cut everything to fit.  First I had to remove the pin from the hinge.  Use the side of the hinge that has 3 barrels, not the side with 2.  This will enable the connectors to reach in their traditional position.  Next, select a 5/16" drill bit and drill out the one of the outermost barrels in your first hinge.   

Using the OEM connector (the white piece) test the fit.  Mark a line where material is to be removed to allow the key to fit.  Remove material with a rotory tool or hack saw.  The fit between the OEM connector and the hinge has to be incredably tight.  The amount of torque that is aplied to this piece in insane.  Be patient, b/c you will probably have to install, test, remove and tighten several times before you get it right.

Select 1/8" rivets and drill required holes in the hinge to attach the door, and attach door.

Now that your door is assembled, trim it to fit using the old doors as templates.  These new doors will fit very well, and will not work if they are even 1/16" too large.  Be sure to pay attention to the side that the notch is removed from - It needs to be on the opposite side of the connector.

Repeat steps 2-5 for the other door. 

Cut the head off of one of the hinge pins to serve as the connector between the 2 doors.

This step requires the most patience.  To install the far blend door you will probably not be lucky enough to have the connector key in the right place.  No worries - disconnect your battery for about 30 seconds and reconnect.  This clears the Automatic Tempature Control computer and it will run the calibration test automatically.  Turn the ignition to run and turn the climate control on.  The actuator will begin to rotate clockwise.  Once the key is in the correct position turn off the ignition and disconnect the battery. 

Push the new door onto the connector and slide the connector pin all the way into the installed door. 

Install the second door, sliding the connector pin into the far side of the second door.  Align and snap in the near connector. 

Reinstall the near actuator and test.  When you put the ignition to run and turn on the climate control system it will run though the calibration test that broke the OEM equipment to begin with.  Watch the doors move, and pay attention to the amount of torque applied to the doors - the plastic ones didn't stand a chance!  Be prepared to remove and tighten the connector / hinge mating.  Once you are satisfied the connection is secure, duck tape the doors to cover the holes.  Replace the cut piece of plastic and tape, and you're finished.  Now...what to do with all that money you saved...hmm....