Recirculation flap motor problem

[bobthebuilder]

My A/C has just not been cooling the car down on this hot, humid days like it used to. I tracked the problem down to the recirc flap not moving from fresh air to recirculate. I pulled the recirc flap motor out and found the white plastic arm intact but the shaft was broken. I picked up a couple of replacements from the local u-pull lot, yet did not have enough good parts to make one. Mine had good teeth on the big white gear, and the other two had stripped teeth on same gear. I cut the shaft off one of the donors and super glued it to my gear. Super glue seems to holding good. Got it all back together, and tested before re-installing. The white arm extends significantly past the stops in both directions of travel. In the picture, the arrows point to the stop bosses on the housing. I stuck the arm on the outside of the unit for testing so I wouldn't break something. Unfortunately, I don't have another large white gear to test with. I'm pretty sure I properly oriented the shaft before gluing it on. What could I have done wrong, or is something else wrong? I know I can order a new gear set online, but it's $60, and I don't think it will make a difference. I have motors from three different year 9-5's - donors provided from an '01 and '03, mine is '04. They look identical.

Thanks for any help you can provide. I'm so close resolving this!

[bobthebuilder]

Did some tinkering with this thing tonight. If I disassemble the unit and have the bare motor exposed, then apply 12V, the motor runs continuously. It does not stop after "x" seconds or rotations. That tells me that it senses when the bosses on the underside of the big white gear hit the protrusion where that gear goes through the motor case. You can feel those stops by rotating the big white gear by hand. It has maybe 120 degrees of rotation. I also tested all three units and they all rotate the same number of degrees, and all extend past the stops on the motor cover (picture above). It stands to reason that it would also stop when the white arm hits the stops on the motor cover. So, going for broke, I reassembled my one good unit and applied power. When the white arm hit the stop, there was a momentary pause, then a snapping sound. Shazbat. A closer look and I could see that the shaft I glued onto the big white gear had snapped off on the glue line. So, now I need to decide if I want to drop $60 for a new gear set which would have the big white gear and shaft intact, and presumably, much stronger than my repair. Has anyone had any experience with these units? I see a lot of posts that this is a known failure part. I'm not the only cheap tinkerer trying to repair rather than replace!

[DnstrDan]

The problem with stressed plastic mechanical parts is that they degrade with age and will eventually fail. That's why rebuilding the ACC recirculation assembly with salvaged parts is problematic. You are correct in how the recirculation motor works; it's different than the other three motors used to control the distribution and blending functions which are of the stepper type. I recommend you purchase the Skandix repair kit from eEuroparts, at about $80 one can avoid the extra expense of shipment from Germany. John Schreiber has a great writeup on the repair of this component that I heartily recommend reading.
I performed my repair over a year and a half ago, and it's still holding strong. One enhancement I added was reinforcement of the black plastic stop on the inside of the case. It had sheared off, but fortunately I found the broken piece when I opened the case. When gluing it back in place with epoxy, I added a reinforcing fillet along the outside perimeter.