AC Knob-Bezzle broke Off - how can I replace myself?

Welcome aboard. That might be a tough one as using glue might cause it not to slide to open/close if not done correctly. Gorilla glue is very good though if you can figure it out.

 

It wouldn't hurt to drop by the dealership to see what they have to say... if you have a good shop foreman they may look at it for free.

 

I just took a quick look at mine, and it appears that even glue wouldn't do the trick on this one. From what I can see, the diffuser lever (the part you move left/right/up/down) snaps into that other pieces, which is what moves the actual "fins" left/right inside that vent.

My recommendation, would be a small piece of tape on the back of the piece that goes inside the vent section and try to get it into place (you can use a small poker/screw driver/etc to reach in and pull the tape through the top or bottom of the vent) and you should be able to put rearward pressure on the lever part to have it snap right into place.

Another option, besides tape, would be to use a small cable tie to, and cut it down slightly to wedge it inside the little fins (I can't tell how wide they are, or if this would be a viable option), and that would allow you to get it into place.

Otherwise, I'm not too sure what else might work. It looks like once that back piece is set into place right, you'd be able to put backward pressure on it. You might want to try to find a small piece of fabric or something to wedge inside the vent area, just in case you drop that back piece and it manages to align just right and fall inside the vent to where you can't reach it!

 

Does the whole vent cover/fins snap in and out? You may have to buy one.