Climate control Airflow selector knob

[ROBinGa]

So I've been reading the threads past few days about the recirculation door issue for Max AC, and also exterior air inlet. Don't think we are having the issue with the Max AC problem. But rather the selector switch to the far right that controls where the vent, floor, defrost, etc. air flow is diverted doesn't seem to change airflow source. If it's set to all vent or all defrost the air still comes out of the front vents. I do have all four speeds from fan selector and it does change in volume from 1 to 4. Also the temperature selector is working so that heat comes out when in the red and cool air when in the blue. So is there a fix for what I am describing with the selector switch on far right not changing where the air comes out? I haven't done anything at this point other than diagnose that the selector does not affect where air flow blows from. Update actually I think air is coming out of vents and defrost and floor all the time regardless of where the selector shows it should be coming out.

 

[Number4]

If you drop the glove box (push in the tabs so it hangs to the floor) and shine a light up in the area of the radio, you'll see a vacuum actuator. When you select the different vents it'll most likely move in and out (actuator rod will be facing the passenger compartment, away from the engine.) Only problem, is that it's not connected to anything anymore. The actuator exerts too much force on the under engineered plastic piece that attaches it to the diverter flap and it snaps.

 

[ROBinGa]

Numer4 you were exactly right. So my plastic part that the actuator arm used to attach to looks like the plastic nub or post that the hole of actuator arm fitted on is missing. There is a small white circle there making me think it stressed and broke flush with the part. And the end of the plastic piece is still intact unlike other photos of this broken plastic piece I see in other threads where the tip breaks off and others have made a piece from sheet metal to fix. My plan is to take Dremel and small bit and simply make a hole where that small white stress mark is in the plastic. Then I could either fit a small screw and nut or zip tie to connect the actuator arm. I moved the selector switch and the actuator arm works and if I move the tab manually I can divert air to vent or defrost. Thanks Numer4

 

[ROBinGa]

Well my fix with drilled hole and zip tie worked ok for about 5 minutes. I was just about convinced it was good and putting glove box back when the zip tie snapped. The selector was to vent and the actuator arm is very strong in pulling the arm back. So I tried another and when cinching that one up broke the tip off plastic door control arm. So now my broken arm looks like all others in pictures. If anybody has done this repair did you take the actuator motor off its screw mounts? I had devil of a time getting the actuator arm in exact position and wondered what is best way to align the holes when I guess I go the sheet metal wrap route?

 

[Number4]

Dealer told me the actuators go bad (still work) but over extend. I suppose when they go in. In one thread a sheat metal screw was set into the actuator arm to keep it from retracting too far.

During the winter, I insert a piece of plastic between the body of the actuator and the diverter flap arm, forcing it to defrost. I'll fix it some day. Both of my 3rd gens have this problem.

 

[ROBinGa]

So over the weekend I decided to make a metal piece with slot to fit over the raised plastic ridge and a hole to fit a screw to the actuator arm. I first used some model airplane acrylic paint to paint the top of the plastic ridge on the door arm tab. I then put an index card to the wet paint so I would have the outline of shape of the raised plastic ridge. That became my shape example to keep in case I messed up along the way. I then traced the paint pattern once it dried to another index card and cut out the pattern with xacto knife and cut the card down enough to fit the card over the tab on door arm. I then marked the card to final shape and traced my card template onto the metal. Using my drill press I carefully drilled several holes to make the slot to fit onto the tab. I carefully rounded the slot and kept fitting until it was just right to fit snug on the tab of the door arm. I also had about 1/8 extra material on the left side of the metal piece that I bent around the edge of the tab making it that much more snug to the plastic tab piece. It's not coming off unless I take it off. To attach the arm I used a screw and 2 nuts figuring the first nut would loosen over time and the second would prevent that. It is working great and the front vents now get full volume and defroster can be full defrost when selected.

 

[1992explorer]

I have this same problem. Is epoxy not strong enough to bond the pieces together again? Or will it just end up breaking in a month or so?

 

[Dave8338]

Not enough surface area to keep things glued together. It may work for a few cycles but isn't going to last over the long term.

 

[ROBinGa]

My opinion is the actuator arm force is so strong it is breaking these plastic tabs. It pulls the arm well inside the mouth of the actuator when the fully open vent position would keep the arm about 1.25 inches outside the mouth of the actuator. i doubt glue would survive the stress. There are several other posts on this topic where guys have drilled a hole through actuator arm and put in a long screw with nuts securing it on either side of the actuator arm so that it prevents the arm from being pulled further into the vacuum actuator than needed to fully open vents. The fully extended arm position selects the defrost. I may do this to mine on another weekend to make sure I don't stress my repair.