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Heater / AC Blower Stuck in Defrost mode

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Old 07-13-2011, 09:49 PM
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Default Heater / AC Blower Stuck in Defrost mode

I have a 2002 Dakota and for a while now my blower controls will not switch from defrost to the vents or floor.

I’m pretty sure this is vacuum related but I do not know where to start. I do not want to just start ripping my dash apart until I have a good idea of what I am looking for..or where to look
.
I have been told it could with be a loose vacuum hose in the dash or a bad vacuum module.


Any input to this or where to start?

Thanks!
 
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Old 07-13-2011, 10:14 PM
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Welcome to the Forum..

It is not a vacuum actuated system, your truck has electric actuators that operate the blend doors on and in the HVAC housing box. There are two actuators inside the housing that operate internal blend doors. You have to remove the entire dash and HVAC housing to open the housing up and replace or fix the internal actuators and check/replace the blend doors if they are broken. That is a lot of work but it can be done if you have the right tools and the time for the job. It also involves evacuating and then re-charging the AC refrigerant.

There is a blend door actuator outside the HVAC box, it is up above the gas pedal. You can remove the knee bolster panel from the bottom of the driver's side of the dash and get under there with a good shop light so you can see while a helper operates the AC and vent controls. Maybe see if the actuator is broken or not moving at all, or maybe it is just unplugged. Because of the location of the actuator it is easy to accidentally kick it with your foot and knock it loose or break it. You can replace that actuator without removing the HVAC housing but you have to be able to remove and reinstall it by feel, there is not much room up in there to work. There is a fourth actuator up behind the glove box, it works to change the fresh/recirculate air intake. From what you described, it is probably still OK.

I have seen posts here on this problem. Maybe search here and on www.dakota-durango.com and there is probably a lot more info and pics online about it. Good luck with it.

Jimmy
 

Last edited by 01SilverCC; 07-13-2011 at 10:16 PM.
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Old 07-18-2011, 11:45 AM
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thank you for the reply..sounds like it won't be an easy or cheep fix.....should start thinking about selling or trading it in? ..lol
 
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Old 07-19-2011, 01:07 PM
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Its not as bad as you think. It does suck, HOWEVER its only a couple day project. some special tools would be required. dash does need to come out, but thats the hard part. pretty easy after that point. Above post sounds pretty right, either a blend door issue or a control panel issue.
 
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Old 07-19-2011, 03:06 PM
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I don't think there are actuators inside of the housing. I just took mine apart and everything was mounted on the outside of the housing. There are doors on the inside, and yeah, if they are broken, you will need to fix them, but there is a good chance it is the actuators on the outside. Also, I don't think you will need to evacuate your AC system for this repair or remove the entire dash. This only needs to be done when removing the housing, which you shouldn't need to do unless the doors themselves are broken.

Apparently, per the FSM, a dealer scanner should be able to help. "The mode door actuator can be diagnosed using a DRBIIIt scan tool. Refer to the appropriate diagnostic information."
 
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Old 07-19-2011, 03:44 PM
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Sorry, I thought there were 2 actuators inside the HVAC box. I have never had mine out of my truck and God willing, I will never have to take it out of the truck, either.

Jimmy
 
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Old 07-20-2011, 07:11 AM
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I think there are 2 or 3 actuators, I should remember since it was just 3 days ago, but I know at least 2. They can probably be accessed from the drivers side if you remove the bottom portion of the dash and maybe the snap on front plate for the dash. They are held in by only two screws each, but one of them is also holding some gearing in place so when you do remove it be sure to mark which direction the gears are facing since you will need to replace the new actuator in the same direction and match up the spindles.

I didn't replace my actuators when I did my heater core because it seems like you can get to them without too much work. Depending on your skill level and if you have ever taken your dash apart, I'd say you could finish it in about five hours your first time. Just mark everything, and if anything doesn't come off of the dash FAIRLY easily, you probably missed a screw.
 


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