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-   -   Blend Doors revisted again (http://www.jeepgarage.org/f77/blend-doors-revisted-again-48697.html)

Knighthawk36 10-11-2012 09:23 AM

Blend Doors revisted again
 
I know this has been posted many times before. I tried to post it on another thread, but evidently no one noticed. I know that most people that read this post are going to have a knee-jerk reaction and say blend dorrs, but I am not certain that is the case here. Please read my reasoning careful and help me determine what the problem is.

First from the AZC diagnostics, I get a 22 Driver's side blend door travel too large or something like that, which of course tells me that the blend door on the driver's side is broken. But here's the rub: I took the driver's side actuator off and found that the female connector on the acuator that turns the blend doors open or closed was cracked pretty severely, so I replaced it. This fixed everything... for about two months, then it started again. I tried recalibrating and it didn't fix it. I checked to see if it was broken again, but it wasn't. But while I had the actuator off, I realized I could turn the knob that manipulated the doors by hand (the stops are NOT broken). If I leave it where it is, it blows cold air. If I turn it counter-clockwise, it blows hot air and stays in that position until I stop the fan, then it goes back. This doesn't sound to me to be a blender door problem, could there be a problem with the new accutaor or one of the control modules?

Frango100 10-22-2012 10:05 PM

Re: Blend Doors revisted again
 
Do you still have the travel too large message? And also after the calibration, the message is still there? How does the system behave without looking to the fault codes. When selecting hot, does the door move? When selecting cold does it move? This is a quite simple system without any end switches. It just calibrates itself once in a while by moving all doors fully open and fully close ( until the end stops) and just waits until the actuators stalls to know what the end stop is. If the travel is too large, but the end stops are still intact, then there must be some possibility for the actuator to rotate without moving the door. That could be inside the actuator as well. Try to hold the actuator shaft by hand while selecting a different temperature and see if you can hold the shaft and still hear the actuator turning.

Knighthawk36 10-29-2012 02:46 PM

Re: Blend Doors revisted again
 
Well the actuator doesn't move at all except during calibration. When I clear it and have it calibrate, it keeps going clockwise WAY past where the stop should have stopped it. I don't understand how it is doing that, except I did see the acuator pull back from the knob it is supposed to turn enough that I am afraid that it is going to strip the mounting screws. Yes it has cold air on the driver's side when it should be warm, but if the blend doors are goofed, why does it does both sides stay nice and tasty when I turn the knob by hand?

Frango100 10-29-2012 06:02 PM

Re: Blend Doors revisted again
 
When an end stop breaks, not too long thereafter the connection between the actuator and the door will break or at least will create enough play for the actuator to continue rotating. It will not continue rotating, but it will time out and the actuator freezes. When you do the calibration, the actuator will rotate again, but after a certain time it times out again.
So there must be something wrong with the connection between the actuator and the door.

Knighthawk36 11-30-2012 03:09 PM

Re: Blend Doors revisted again
 
But what I don't get is that the knob that the actuator turns has stops going both ways. How does the actuator keep turning WAY beyond those stops?

Frango100 11-30-2012 06:59 PM

Re: Blend Doors revisted again
 
You can see it easier then we overhere. There must be something which should act as an end stop. If the actuator knob doesn't stop, then probably the end stop pins are gone. If the knob touches the stop pin, but the actuator continues running, then probably the actuator knob is cracked.

Knighthawk36 11-13-2013 03:52 PM

Re: Blend Doors revisted again
 
I know this is an old Thread, but as an update, I finally got enough money to take the Jeep to a mechanic. He just called me and said that the dash is laying on the floor and the box is out, and the blend doors are working fine. Now they are doing a complete diag to find out where the problem actually is.


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