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-   -   a/c only from defrost vents (http://www.jeepgarage.org/f203/a-c-only-from-defrost-vents-45885.html)

jrsummersill1 08-10-2012 12:47 PM

a/c only from defrost vents
 
I have a 00 jeep grand cherokee limited that is only blowing air from the defrost vents and has no heat whatsoever (not really worried about the heat right now). I know that the defrost vents are the default when there is a problem. I performed the azc self-diagnostic test and got the following codes:

13 = AI (Recirc) motor not responding
20 = Mode door travel range too large
22 = Left temperature door travel too large
24 = Right temperature door travel too large

Anyone know what these codes mean exactly and how to fix it? By the way, I also calibrated the azc system, and that didn't fix it.

Thanks!

Frango100 08-10-2012 10:51 PM

Re: a/c only from defrost vents
 
Welcome to the garage.
It is in fact the manual AC system which has the defrost mode as the default mode. This system uses vacuum actuators and when vacuum is lost, its defaulted to defrost mode.
The AZC system has in fact no default position. This system uses electrical actuators and can get stuck in any position. An actuator "too large" message normally means that the end stop is broken or the door hinge itself, causing the actuator to travel too far or even continue rotating for a certain time.
The mode door is stuck in the defrost position, do you still hear the mode door actuator moving when you select an other mode? Did you disconnect the battery for a few minutes to see if all codes stay as is?
If all codes are hard faults, it probably is time to remove the complete dash and the HVAC housing to see what is really broken, but it seems that the mode and both blend doors are broken.

jrsummersill1 08-11-2012 10:12 AM

Re: a/c only from defrost vents
 
Frank,

Thanks for the reply. Are the mode door and blend doors the same or three different doors? I don't mind fixing this myself, but don't believe that I am skilled enough to remove the dash. What's your take on going in behind the glove box? It appears from a google search others have done it successfully.

Are the blend doors for the heat issue and the mode door the a/c?

Thanks in advance for your help and the welcome. I will be coming to this site a lot I think as there are numerous issues with my jeep and I don't have the money to have the dealer fix them all. lol. I'm just taking them one at a time.

Jenny

Frango100 08-11-2012 11:31 AM

Re: a/c only from defrost vents
 
Hi Jenny,
The mode door is the one who regulates the air from windshield to feet or vents. It is one door with one electrical actuator.
There are 2 separate blend doors, one for the drivers side and one for the passengers side. Air coming from outside, or inside when in recirculation mode, always passes through the AC condenser and then can bypass the heater core, or (partly) go through it, depending on the heat request.
There is an alternate way to repair the blend doors, i think its called heater treater, and when done this repair you will only have one blend door, so equal temperature on drivers and passengers side. This repair can be done through the glove box and doesnīt require the dash to be removed. You have to cut a hole in the HVAC housing to get access to and to replace the blend doors for only one door.
But i donīt think that there is an alternate way to replace the mode door. Eventhough it seems to be a job for a whole day, if you could get help from a friend or so, you could fix it yourself and safe a whole lot of money. Many people, ofcourse depending on the financial possibilities, also replace the heater core and AC evaporator once they have to remove the HVAC housing.
Did you disconnect the battery already to see if all codes return?
Once fixed this one, tell us the next problem and we will try to help out.

Frank.

jrsummersill1 08-11-2012 09:32 PM

Re: a/c only from defrost vents
 
Is the mode door also called the recirc door? Or are they two different doors?

Thanks, Jenny

P.S. I would have thanked your posts, but have not figured out how to do so.

Frango100 08-12-2012 05:54 AM

Re: a/c only from defrost vents
 
1 Attachment(s)
No, the recirculation door is the one who lets or outside air inside the cabin, or lets the air recirculate inside the cabin. That is a different door then the mode door.
Attached a page from the WJ manual, which shows the HVAC housing when it is split open, to show all the components inside, just to give an idea.
Donīt worry about thanking, you did in fact already in your post:D.
For some reason only paying members have the possibility to say thanks, so donīt look further for that.

jrsummersill1 08-12-2012 07:29 AM

Re: a/c only from defrost vents
 
On the diagram that you attached, which number is the mode door?

4.7ho 08-12-2012 08:31 AM

Re: a/c only from defrost vents
 
3 Attachment(s)
Number 11

This is def. not a job for the faint of heart though it can be done in a day. I've attached some pics of what you will be looking at if you do attempt this job yourself and added some links to help with dash removal. You are for sure going to need a new recirc door actuator motor since your has stopped responding ie.. dead. If you plan on keeping your jeep for a while it would be wise to invest in a new evap. coil as well as a new heater core since you will have access to those components while in there and if you never want have to worry about the blend doors or recirculation door breaking again after doing the repairs I recommend buying new ones from blen dor store as they are made from aircraft grade aluminum and are what I used when I did mine and never had another issue with either afterwards since the new doors/shafts are far stronger than the force the actuator motors are able to produce. I don't know if he does a mode door replacement since mine was fine and you may have to order that one from Jeep itself but i wouldn't recommend replacing the blend doors with OEM since they will likely break again due to their poor design.

http://www.wjjeeps.com/hvac_sub_assembly.htm

http://www.blendorstore.com/home

jrsummersill1 08-12-2012 10:23 AM

Re: a/c only from defrost vents
 
Thanks for your help. I think that for now this fix will have to wait awhile. :( I'm not too keen on removing the dash just yet.

We had the engine rebuilt a year and a half ago, and I think that when they put the engine back in, they broke the door because it's been like this ever since. For the time being, I put a small fan on the dashboard to pull the air through the car. Not the same as having the front vents working, but does help a little in this Florida heat.

Frango100 08-12-2012 11:43 AM

Re: a/c only from defrost vents
 
1 Attachment(s)
They would not be able to break any HVAC door when changing the engine. You could have a look at the mode door actuator and maybe even change the position of the mode door, see attachment.

jrsummersill1 08-12-2012 04:02 PM

Re: a/c only from defrost vents
 
Thanks again Frank!! I will try this in the next few days and let you know how it works out.

jrsummersill1 08-12-2012 04:59 PM

Re: a/c only from defrost vents
 
2 Attachment(s)
These are pics from under the dash, under the ac. There is an opening. Do you think that this is the arm for the mode door?


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