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Unread 03-26-2010, 12:01 PM   #1
klockdoc
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Heater flap control problem

I have a 1998 GC Limited. I am having trouble with the flaps opening. Orrecty. If I turn on the heat, air only blow a out of the bottom. I cannot get at out of the defroster or the upper dash vents. Does anyone know what controls this? It has automtic ttemperature control. Cannot get air out of other vent. Darn ipod key pad.

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Unread 03-26-2010, 04:04 PM   #2
charonodaemon
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1998 ZJ 
 
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Just had that problem and it is a bit of a pain. There is a control arm under the driver side on the a/c unit connected to an actuator. If that control arm is not connected to the blend door it won't change modes. The biggest pain about it was removing the dash to get to it. You can check it visually to see if it is connected or not.
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Unread 03-26-2010, 05:22 PM   #3
klockdoc
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Quote:
Originally Posted by charonodaemon View Post
Just had that problem and it is a bit of a pain. There is a control arm under the driver side on the a/c unit connected to an actuator. If that control arm is not connected to the blend door it won't change modes. The biggest pain about it was removing the dash to get to it. You can check it visually to see if it is connected or not.
I was wondering if possibly it was in the electric circuit somewhere? Something must control that actuator arm electrically. because you can adjust whether the air is directed through the defroster, air on the floor, air on the floor/upper vents, upper vents only...by use of the auto temp/heater selection knob.

My control also acting up, when you turn down the temp (with the blower on auto [and it is running on high mode]) the blower keeps running full blast! It used go to the low blow when you reached the car temperature. So, I was wondering if this control was possibly bad?
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Unread 03-26-2010, 07:15 PM   #4
charonodaemon
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There is an electric actuator for the the mode change door. To initially check for actuator problems or any other fault codes there is a reference guide on this site for the ATC control module for deciphering which faults you have encountered. Can't remember the link for that reference guide, but you should be able to pull a search for ATC problems at the top of the page.

I have come across bad controls as well, had a burnt up IC chip on my original one.

Does the controller try to change modes when the cabin temperature is at a given point and you change the temperature setting?

A few more details may help to pinpoint the problem.
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Unread 03-26-2010, 08:23 PM   #5
klockdoc
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Quote:
Originally Posted by charonodaemon View Post
There is an electric actuator for the the mode change door. To initially check for actuator problems or any other fault codes there is a reference guide on this site for the ATC control module for deciphering which faults you have encountered. Can't remember the link for that reference guide, but you should be able to pull a search for ATC problems at the top of the page.

I have come across bad controls as well, had a burnt up IC chip on my original one.

Does the controller try to change modes when the cabin temperature is at a given point and you change the temperature setting?

A few more details may help to pinpoint the problem.
I remember when I first purchased the Jeep, the control would light up for defroster (in the winter when the windshield was cold), or lower/upper vent combination. The unit only stays on the floor setting now. Does not change when you adjust the temperature control.

I will have to check and see if it comes out the top when it goes to air conditioning.

It never automatically adjusts for defroster now.
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Unread 03-26-2010, 11:26 PM   #6
klockdoc
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Possibly good news. When I got into the Jeep tonight, the air flow indicator for the direction was pointing towards the defrost sign. It only stayed lit for a short period....but in that short period, the air DID blow out the dash air vent. So I guess that rules out the actuator arm problem. (Hopefully).

If I turn the indicator knob off of auto and into manual, the change in direction does not work. It only blows out the bottom vent.

Any thoughts?
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Unread 03-28-2010, 06:59 PM   #7
charonodaemon
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Ok, good start. Does the indication change at all on the display? If so, you may want to look at the actuator itself, which is under the driver side dash on the a/c box to see if that tries to reposition. If it tries to, it may be the connecting arm coming from the actuator to the mode door having become disconnected. If the actuator does not move let me know. I have some other suggestions to check if you have a multimeter.
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Unread 04-03-2010, 11:27 AM   #8
klockdoc
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Quote:
Originally Posted by charonodaemon View Post
Ok, good start. Does the indication change at all on the display? If so, you may want to look at the actuator itself, which is under the driver side dash on the a/c box to see if that tries to reposition. If it tries to, it may be the connecting arm coming from the actuator to the mode door having become disconnected. If the actuator does not move let me know. I have some other suggestions to check if you have a multimeter.
Sorry for the delay in getting back to you, work you know. I had some time to check it out this morning. The actuator arm, (small wire operating a white plastic arm, moves when I manually change the knob position from floor to floor and upper vents. But, no air comes out the upper vents. Only stays on the floor.

I tried to run a diagnostic check on the ATC control, but it did not work. I guess it has to show an ER code before it finds any fault. (Unlike the CEL)

Hope this provides some additional help in locating the problem.
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Unread 04-03-2010, 06:19 PM   #9
charonodaemon
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So it sounds like the actuator is trying to control the repositioning of that mode door. It sounds like the connecting end to the mode door is not in place correctly. If you have the time and patience to check on something and see if that connecting arm is loose, on the end that is on the ac box, not the actuator. It is a bit of a pain to fix it. If that end is loose, it will take some doing and the dash will have to come out to make any attempt to reconnect that end. The ac box doesn't have to come out, but it will be a bit trying on the patience and hands etc. Let me know what you find on that end not connected to the actuator, but the ac box.
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Unread 05-22-2010, 05:06 AM   #10
Pyrate_7
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I had the same issue. When I crawled under the dash, I found that the PO had removed the actuator and left it sitting on the floorboard, and the control arm was broken in the glovebox. Anybody have a part number for the control arm? It's not showing up in the Haynes manual for some reason.
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Unread 05-23-2010, 04:01 PM   #11
charonodaemon
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I have images for the entire A/C box from the dealership, but with no part numbers. You will have to call them and get the part numbers and prices.

And to Klockdoc, I have images of the control arm for the mode change actuator that may be your problem.

I will dig through what I have as well and start a thread on the break down and modifications for the drain tube and refoaming of some of the blend doors. Hopefully the modification will prove worth while to keep water/condensate from collecting and pooling in my front passenger floorboard.
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Unread 05-26-2010, 11:28 PM   #12
klockdoc
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Quote:
Originally Posted by charonodaemon View Post
I have images for the entire A/C box from the dealership, but with no part numbers. You will have to call them and get the part numbers and prices.

And to Klockdoc, I have images of the control arm for the mode change actuator that may be your problem.

I will dig through what I have as well and start a thread on the break down and modifications for the drain tube and refoaming of some of the blend doors. Hopefully the modification will prove worth while to keep water/condensate from collecting and pooling in my front passenger floorboard.
Would be interested in seeing the images.

Also, haven't eliminated trying to fix the problem. My daughter has a 1998 GC and her husband has to replace the evaporator. I thought I would wait until we pull the dash out of her car and see if I can get a better look at what might be causing my problem.

When my air conditioner is turned on now in the auto mode, The indicator shows air flowing through the upper vents. Problem is, air only comes out the lower (heater) vents and through the upper side vents.

Hopefully I can get a better idea when the disassembly begins.
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Unread 05-27-2010, 04:31 AM   #13
charonodaemon
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Will try to get the image of the control arm loaded up for you when I get off of my shift today. Pulling the dash and A/C box is not as hard as one would imagine, but understandable as to why shops want to charge and arm and leg to do so. The biggest pain with doing so is removal of all the wires required to release it. They did a couple of things right by color coding the plug-ins on the fuse box.
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Unread 05-27-2010, 03:25 PM   #14
klockdoc
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dash

Thanks. I got lucky with my daughters GC, my son in law and I took the dash out of a GC at a pick and pull junk yard. It didn't take long at all. Of course I didn't have to remember where to replace the wires on the junker.:-)

Also the windshield was missing which made it a lot easier. If I can't get my son in laws butt in gear, I may need to go back down and pull another one apart just to remember how.
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Unread 05-27-2010, 06:28 PM   #15
charonodaemon
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Here is the image of the control arm linkage for the mode door actuator. As I found mine when digging into it the end connecting to the actual damper/flap was disconnected. This may be your issue. You can put it back on without removing the A/C box, but it takes patience since it is slotted. I made sure the damper itself was lined up properly with the dash out and tapped the top of the other end to make sure it seated right and the lock tab was in place. Hope this helps you. It would be the round connection on the right of the picture.

Something else to make the upper screws easier to remove is a small ratchet/screwdriver set I got from radio shack.

http://www.radioshack.com/product/in...ductId=2062777

It is a very handy device for the screws holding in the top of the dash as well as the two on the sides to get the lower portions out.

Good luck and let me know what you find.
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