Design Study: A look inside the Saab A/C Vent

I confess: I am a complete sucker for elegant and clever engineering/design.  Notice how I lump both “engineering” and “design” together, almost as if any distinction between the two only bear significance to the likes of Merriam and Webster?  No one could put it more succinctly than the late Steve Jobs: “Technology alone is not enough. It’s technology married with the liberal arts, married with the humanities, that yields us the results that make our hearts sing.”  Yes, I admit, comparing the Saab A/C vent to let’s say, an iPhone, is pretty silly.  But, when it comes down to aesthetics and sheer ingenuity, this is a truly impressive piece of design.  While most auto-manufacturers are content with independent X and Y axis control: Saab has managed to engineer a vent that allows complete freedom-of-motion across the X-Y plane.  It’s a feature that I’ve always appreciated in my Saab 9-3.  But, I never expected to get an inside look into this curious contraption: until it was time to install a complete Hirsch interior upgrade package.

Ideally, when removing the various components to perform a replacement of the dashboard, each component should be extracted as one piece.  While this remained true for most parts, the air vents appeared to have this innate desire to spread it’s glory all over my 9-3s cockpit.  Granted, this maybe a testament to my utterly sad level of proficiency as an auto-mechanic, but no-one could ever fault me (or my wife) for executing such a task with great care, as we have.  After removing the Saab 9-3 air-vent, the sinking feeling of watching it’s internals separate, transformed itself into an opportunity to understand how this marvel of engineering actually works (as we would have to reach this level of understanding in order to properly reassemble it).   The vent contains two stacks of plastic grid plates.  When aligned in their central position, air flow will be guided towards the direct front of the unit.  But when the knob is pointed in any direction the alignment of these plates will change.  It turns out that these plates rest on a U-shaped peg, which is on the reverse side of the knob.  Rotating the knob in any direction will result in the plates reorienting in a way that will allow air-flow to point the same direction which the knob is facing.  While removing the Saab air-vent, aside from disengaging the tabs holding it in-place, we have inadvertently disengaged the the tabs holding the unit together.  This led to the plates separating from the knob, while allowing a few key pieces to fall from the unit, in the process.  These pieces happened to be crucial to ensuring that the plates remain in-place, as the knob is repositioned by the user.  Each stack of grid-plates must be supported by a plastic rail.  Each rail is intended to allow a plastic end piece of a stack to slide across it.  Our first attempt to reassemble the vent was disappointing.  While the left side of the vent was functioning perfectly, the right side felt a little stiff.  The end stack end-piece was not gliding across the rail very smoothly.  Clearly, something was missing.  Upon removing the plastic rails, we noticed that there was a missing piece.  One of the plastic rails was missing a thin metal rod, which was supposed to be positioned directly behind it. Fortunately, after looking around the cockpit, I was able to find the missing rod, resting below the driver-seat.  After placing the rod in the back-end of the unit, directly behind the plastic rail, the original smoothness of the knob’s motion returned and all was well.  But when reassembling the Saab air-vent, there are a few important considerations to take into account.  Firstly, the plates must be arranged in the proper order.  One indication that you have succeeded in completing this first step is that the top-most plates will contain a shelf, upon which the end pieces can be placed.  Once the metal rods and rails have been properly inserted into the vent end-piece, there is one final step: snapping both the front and back pieces into one.  This is easier said then done.  Not only will you need to line up the tabs that fasten the unit into a single piece, but you will also need to ensure that the plates remain properly stacked while the stack end-pieces are directly in-line with the rails, as both halves of the unit are brought together.  Don’t be surprised if you find yourself making multiple attempts to get this final step right.  Fortunately the A/C vent is easy (perhaps too easy) to re-separate.  If the knob motion is not smooth or the pieces appear to not be sliding in the expected fashion: you most likely have made a mistake, and should try again.  In retrospect, I am actually happy that I had a chance to take an inside look into the Saab A/C vent.  Yes, it was quite unnerving to see it unintentionally opening up while removing it,  but having a look inside: it’s design isn’t nearly as intimidating as one might think.  It truly is a model of elegant design and engineering.  In the process of replacing my dashboard, two of these vents had to be removed and reinserted (both the center and left driver’s-side vents).  While I unintentionally dissembled the center vent, I was able to remove the left vent without incident.  Thankfully, the remainder of my Hirsch interior installation proceeded relatively smoothly (minus some major annoyances: which I will get into later).  Do stay tuned for a complete discussion of my experiences in installing the Hirsch carbon-fiber dashboard, glove-box trim, shifter plate, and door trim!