Air flow

Tiny
MICHAELKERSEY
  • MEMBER
  • 1998 JEEP GRAND CHEROKEE
  • 311,000 MILES
My air diverter is stuck in the defroster mode and will not change to the front vents of the floor vents. The air conditioning works great, just will not divert properly. I have taken the entire front off the dash and exposed the heat/air unit, removed the controls and inspected the connections, and now puzzled what to do next?
Friday, July 5th, 2013 AT 12:20 PM

27 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 34,193 POSTS
This is a real common problem and most likely you got very carried away. If the controls and actuators are run by engine vacuum, the system will be spring-loaded to default to defrost mode for safety. Your feet might freeze but the windshield will be clear. Look for a small hard plastic vacuum hose broken under the hood or disconnected. There will also be a small check valve in that hose near the firewall. Be sure the hoses didn't pull off of that.
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Friday, July 5th, 2013 AT 12:26 PM
Tiny
MICHAELKERSEY
  • MEMBER
  • 2 POSTS
Thank you very much. That was my next move. I'll put it back together.

Thanks again,
Michael
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Friday, July 5th, 2013 AT 12:50 PM
Tiny
CARADIODOC
  • MECHANIC
  • 34,193 POSTS
You're welcome, but before you go through some more work, be sure you really do have vacuum controls and not electronic. You'll see various-colored plastic hoses going to the actuators from the control head. If you have actuators with two electrical wires, you have a computerized electronic system and you may still have a problem in the dash. I'm not really an expert on diagnosing those but I do know how they work.
If it has an automatic temp system it will be electric, if it has a manual temp control it will be vacuum run

See the diagrams below for the locations of the different actuators for your Jeep
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Friday, July 5th, 2013 AT 1:10 PM
Tiny
CKGKIDS4
  • MEMBER
  • 2 POSTS
  • 1998 JEEP GRAND CHEROKEE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
Where can I find the check valve for the a/c air vents that cause the air flow from vent to defrost mode? Is there a picture to help me?
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Monday, February 11th, 2019 AT 6:45 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Look under the hood for a small black plastic hose coming through the firewall. Follow it to the vacuum source looking for any breaks, cracks or leaks. Also follow any other lines that branch off because they may go to a vacuum reservoir (storage tank) and a leak there will cause the same problem. Using a vacuum gauge to determine if you have full vacuum at any given point is the best way to find it. You can cut into the line anywhere and splice it back together with a piece of vacuum hose. Find the broken line, you found your problem.
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Monday, February 11th, 2019 AT 6:45 PM (Merged)
Tiny
01JEEPGC
  • MEMBER
  • 10 POSTS
  • 2001 JEEP GRAND CHEROKEE
  • V8
  • 4WD
  • AUTOMATIC
  • 85,000 MILES
The recirculation button turns on and off (lights up) but does not work anymore, exhaust fumes from the vehicle in front get in the Jeep and the climate control doors open and close several times after stopping and turning off the jeep, how do I fix these two problems?
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Monday, February 11th, 2019 AT 6:45 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Have you checked to see if the door you hear after shutting it off is the recirculation door clicking? If it is you could have a broken recirculation door or recirculation actuator.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
01JEEPGC
  • MEMBER
  • 10 POSTS
No I have not, how do I do that? I believe it's the recirculation door because of the #52 code. Don't know if it's the actual door or the actuator trying to close the door and it can't, how can I tell for sure?
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Does the clicking noise change when turning the recirculation on and off? You will have to pop the actuator off and look and see if the end of the shaft of the recirculation door is broken. Most of the time the actuator fails.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
01JEEPGC
  • MEMBER
  • 10 POSTS
I don't hear any noise when the recirc button is pressed, the light still lights up but that's all, now the engine is running so maybe it's making some noise but not like after it's shut off and it seems to be opening and closing two or three times. Guess the actuator is the place to start. Can you give some info on exactly what to do and look for?
Thanks
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
HANNA74
  • MEMBER
  • 3 POSTS
  • 1994 JEEP GRAND CHEROKEE
  • AWD
  • AUTOMATIC
  • 187 MILES
I have a 1994 Jeep Grand Cherokee whose climate control console is out. The digital display is not lit up and will not do so. All other systems are functioning fine.
The overhead compass and temperature display is working, but the temperature is not reading, it simply says "oc". It did this once before in the winter but came back on without doing anything.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check fuses f6 and f11 in power dist box also fuses 817 and 24 in dash if those are ok then have it scanned if control doesn't light up. If it lights up turn key on push a/c and recirc buttons at same time and turn temp one click then get back with codes if there are any
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Do you have auto climate control or manual control ac?
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
HANNA74
  • MEMBER
  • 3 POSTS
I appreciate you getting back to me so quickly. However, the fuse labels you have do not correspond to my vehicle labels. I did check fuses and all look to be good.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
01JEEPGC
  • MEMBER
  • 10 POSTS
Automatic, dual zone
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Wha t I sent you was for auto temp control and that is what they are listed at. Of course if yo have manual control meaning your don't set the tem p thenit's not correct maybe. Then you will have to get it scannedpic is for manual it will probably need a pro lok at this as it may not be getting power due to a short or the head is bad.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Does that noise change when you adjust the temp on ethier side of the dash? Iam trying to figure out what is making your noise.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
HANNA74
  • MEMBER
  • 3 POSTS
I figured as much but thought I would try anyway. Thank you.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
01JEEPGC
  • MEMBER
  • 10 POSTS
No noise as I change temps, I think this is the recirculation door, have read on the jeep forums that it is a common failure, they say you can micky-mouse it open or some have done it closed for continual recirculation, will that screw up the defrost as the unit will turn off the recirc mode when I turn on the defrost. I like the recirc mode as it makes the a/c colder and I don't get fumes in the jeep. Any opinions will be appreciated.
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Monday, February 11th, 2019 AT 6:46 PM (Merged)
Tiny
HOMETYRE
  • MEMBER
  • 3 POSTS
  • 2004 JEEP GRAND CHEROKEE
  • 178,000 MILES
I have a 2004 Grand Cherokee (UK), I have mist coming out of the vents (not all the time but I have noticed it more at speed).
If I up the temp it eventually stops and it also stops on the recycle option.
Mist does not seem to be oily and I cannot detect a sweet smell.
Cannot see any water in the car but is does drip water under the car when stopped (always has so I assume this is AOK)
I also have an occasional gurgle coming from the vent which I only seem to hear at low speeds or when stationary (could be that I do not hear at speed).
Does anybody have any ideas?
Dave
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Monday, February 11th, 2019 AT 6:46 PM (Merged)

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