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Khaki Nitro Nut
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Discussion Starter #1 (Edited)
Thought I would move this conversation over here so all could benifit from it...
Joined this forum because I have a problem and that is heat blows out the dashboard vents but no heat to the floor and no defrost. Any setting just blows heat out the dash vents. I have been reading many posts on this site. Would like to see a video on how to repair this. I have mixed emotions whether the problem is a heat blend door actuator or something else. Any comments or replies would be greatly appreciated.
Just so we are all on the same page...
There are 3 door actuators on the HVAC system; Mode doors, Blend door, and Recirculation door. The 3 actuators are interchangeable.
Mode door controls where the air goes, Blend door controls temp, and Recirculation door controls outside air/inside air as the air source.
What you are describing sounds to be the Mode doors.
An easy test to see if the actuator is the issue, is to swap it out with the Recirculation actuator.
You do not need to remove one of the two actuators, just unplug it.
Remove one and plug it into the other harness. Test to see if it is working. If it is, then the issue is most likely with the dash control panel.
Since the issue seems to be with the Mode door that is the one I would remove.

Always disconnect and isolate the negative battery cable before working on any part of the Nitro's electrical system, and wait 10 minutes!
Disconnect the wire harness connector from the mode door actuator located on the driver side of the air distribution housing (it will be the higher of the 2 and closer to the firewall).

Remove the two screws that secure the mode door actuator to the actuator mounting bracket and remove the actuator.

While it is removed make sure the doors move by hand, but note where it is to start and put it back into the same place. If you do not do this, you may need to take it in to Dodge to be calibrated. Be sure to align the splines on the output shaft with those in the mode door linkage when reinstalling the actuator. Rotate the actuator if needed (not the doors).

The Recirc actuator is located behind the glove box (top left).

Durring the above test you may get a DTC for the missing mode door actuator.
Caution:
DO THIS AT YOUR OWN RISK!
This post/thread and any others related to modifying/repairing your Nitro in any way, are here for informational purposes only.
It is your sole responsibility to verify the information is correct, accurate, and safe to use.
What you choose to do with the information is up to you.
If you are unsure, please consult a professional.
 

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Khaki Nitro Nut
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Discussion Starter #2 (Edited)
Second part of conversation.
ScarO, Thank You. I have to learn how to properly reply to these posts. I read the newbie section. I'll just wait for my daughter to get home. Anyway thats a lot of good info.. I will attempt the repair myself. Some of the devices you describe I will have to locate. I moved the truck inside my heated garage. Next I'm of to advance Auto to buy a Chiltons book to find all the parts you describe. Then I will attempt the mechanics. I will succeed thanks to you. Thanks again.
Your welcome. I do not believe there is a Chilton's for the Nitro yet. At least I have not seen one. If you do find one be sure to let us know where. I have the 4 volume set of service manuals from Dodge. They are about 7" tall stacked on each other, and weigh in at about 25 Lbs..
 

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Khaki Nitro Nut
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Discussion Starter #3 (Edited)
Part 3 of the conversation;
I was told by a Dodge dealership service rep to use a 2007 Jeep Liberty in place of the Nitro. So I bought a Haynes Repair Manual but it describes how to remove the dash and the heater blower. Nothing about the mode, blend or recirc doors. This book doesn't really help repair this particular problem. When I unplug the negative battery terminal and wait 10 min. do I leave it disconnected or reconnect it to check the actuators? You say to disconnect the wire harness connector from the mode door actuator located on drivers side of the air dist. housing. Is this inside under the dash? is there a picture of this anywhere?
Leave the battery disconnected until you unplug the actuator connector and plug it into the other connector. Then connect the battery again to test, disconnect the battery once again and reconnect everything, and finally connect the battery when you are done.
The reason you need to do it this way is to prevent accidentally setting off the air bags. Even with the Nitro turned off the air bag system is still on-line.

I do not have any real Pics, and the SM only has the cutout view of the actuators with no real specific location viewable.
This is a general drawing but it may assist you.
If you look from the drivers floorboard up and back you should see the blend door actuator with a plug going to it(12), the mode door actuator is higher up and closer to the fire wall (14). The recirculation actuator (4) is behind the glove box.



All 3 are interchangeable, so you could also use the blend door plug-in to test the mode door actuator if you only want to work from the driver floor. The reason I suggested the recirc plug-in is because it would be easier to see when testing in that location, if you are by yourself.

You will need to do the test Quickly since the pulse stop will not be there.
Use the ignition On/OFF while you watch the actuator. Or swap the actuators completely and test them that way to prevent any mishaps.

The actuators use a reversible motor to drive them, so in theory you could test it that way as well, outside of the Nitro, and bypass using a different plug in. But once again you will need to do it quickly.

ScarO, can I remove a fuse so as not to deploy the airbags? And when you say quickly, how much time do I have- a couple of seconds or a minute?
No, there is not a fuse for the airbags. If there was, people could remove it and disable the safety feature. Mfgrs don't want that to happen for liability reasons.
As far as quickly goes, as soon as your ignition key hits the Aux position, the HVAC system turns on. When the HVAC turns on the actuators will start to move to the selected positions on the dials. You will have a few seconds at best if the actuators are not connected to a door.
Options;Swap actuator positions and test in rig. If it works in the other position and the one you swapped does not work in the Mode position. The actuator is not the issue.
Remove actuator and test it outside of rig.
Remove 1 actuator and connect it to a different plug in from another, and test.
All this may be a mute point because the actuator motors don't usually go out.
 

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Khaki Nitro Nut
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Discussion Starter #4 (Edited)
Now we can continue this conversation in this thread...
jpalladino said:
Today I disconnected the battery, removed the mode actuator and switched the wire connector with the blend door actuator. I marked the plastic gear to the housing of the mode actuator and marked the shaft it came from-I assume this is the gear that opens the actual door. Resupplied power and the mode actuator gear turned. I put the mode actuator back into its original position, turned the dial and I could see like a spring dial turn-but I could not actually see a door open or close. There is a grey smoke clear piece of plastic that resembles a horn next to the mode actuator. I tried to remove it but I could not free it. I wanted to look behind it to see if I could see the actual door. No luck. So still no defrost or heat on the floor-either side. What should I try next? The Nitro won today's battle but I will win the war. I will try whatever you recommend. Thank you. :i_rolleyes:
Behind the Mode door actuator is a round piece, I believe this is what you are describing. When you are looking up at the actuator and change the Mode position switch, this round piece rotates and moves the white arm behind it to change the Mode door position. If the round piece is rotating and the white arm is not moving, then it is possible the arm came loose from the round piece or is broken.
If the actuator is moving and the round piece is not rotating then it is possible the actuator is not installed correctly.
But at least we know the actuator is working as well as the controls...
 

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Scaro, I followed your directions to the letter. I made copies of everything and brought them to my garage. Spent about 3 hours on Sunday working on this problem. I put everything back together, reconnected the battery and started the Nitro. Still no heat on the floor and no defrost. Then Monday nite my wife came home and told me the great news-everything works. The Nitro now has defrost and floor heat and dash heat. I can't explain it, maybe the computer reset itself whatever. Anyway, I'm glad I joined this forum and to the members who contribute helpful information to others I thank you.
 

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Khaki Nitro Nut
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Discussion Starter #6
Yeah, glad it worked out. There could have been something jammed inside and the tinkering worked it loose. Anyway, Good News!
 

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Scar0! I Need your help. I am working with this same problem and my vents will only blow air out of the dashboard defrost vents and the floor vents. I took everything apart that i could and I have gained access to the two white arms that control the doors. the top one works fine and is moving freely but the bottom one (which i assume controls the main vents is locked in place and causes the black main actuator gear to "jump" off the track and keep moving without turning the white arm. Do you or anybody else know an easier way to get that box out so i can take a look at what may be inside causing the gear to be seized? I do not want to try and force it because it is plastic and I know something will break, but I am slowly loosing patience. even if it needs to be replaced I just want to know how to get a hold of it so I can bring it to my bench. Any help would be greatly apprecieated!
 

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Khaki Nitro Nut
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Discussion Starter #8
Not sure what gear you are wanting to look at. Did you remove the actuator?
The Mode door actuator is on the drivers side, higher up and closer to the fire wall.
This should be the one with an issue.
Below that one and more toward the center of the HVAC housing is the Blend door.

In order to get to any of the actual "doors" (Blend[hot/cold], Mode[floor/vent/defrost] or Recirc[outside/inside air]), you have to remove the HVAC system from the rig and disassemble it.
I have not tried this, but you may be able to remove the radio bezel and look into the center vent tubes with a light and mirror to see if something got jammed in there.
 

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I got it! what i ended up doing was taking the actuators off the system and looking at all of the (white) gears individually. That actually ended up being no help, because the gears are plastic so you can't really force it or else they will get chewed up. So i went through the radio bezel and found that the middle main vent guide is removable and held in by three screws (One straight behind each flared end, and one in the center/bottom.) That gives you almost direct access to the mode door where I could get my hand inside and move the door manually! To my surprise there was lots of tar-like black crap all over the door which kept sticking (literally) to the vent. Cleaned it up and assembled it all together and now it opens and closes smoothly! Thanks for the details, they really count and helped me from having to remove my entire HVAC system!
 

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Khaki Nitro Nut
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Discussion Starter #10
Your welcome and thanks for getting back to us. :rep:
More great info we can pass along to the next person!
 

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Khaki Nitro Nut
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Discussion Starter #12
Thats the best I could find in the service manual and parts listings.
 

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heat problem please help

hi back :) another problem with my nitro 2008 3.7l , my heat work only on passenger side for all vent exit... on conductor side have no heart... where is my problem ??

thx all
alex c
 

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Khaki Nitro Nut
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Discussion Starter #15

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Khaki Nitro Nut
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Discussion Starter #17
Your welcome. Let us know in the other thread if a heater core flush does the job. :smileup:
 

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Hi, was having the same problem with my 2008 jeep liberty that we purchased used. Internet search brought me here and it was great help. I get under the steering wheel and lo and behold the actuator wasn't even there, just the So i disconnected the blend actuator to move it and test it at the mode door location but there is no gear or there for the actuator to connect to and turn the blend doors. Do you know the part number or where to get this gear? The closest item I found online says its for 2011-2015 Grand Cherokees and Durangos.
 

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Khaki Nitro Nut
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Discussion Starter #19
Hello and welcome to the forumz Brad.
Sorry to say I did not find any part # for the gear in any of the Nitro or Libby (kk) part manuals I have.
For a couple bucks it may be worth taking a chance on.
If you do get it, then please let us know if it works, along with the part #.
The KK and KA have the same HVAC system.
 

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Anyone have a part number for these actuators? Pretty sure I need one for my blend door. Air moves, record works, no heat at all. Core in and out hose gets hot and is pressurized.
 
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