Let's revisit the facelift climate control (abbreviated "CC" from here) for a moment. I've got an older style CC as well as a facelift CC and have done quite a bit of digging in the Bentley manual as well as Vag-com to try to make this work. Some of this information has been posted already, but I'm going to reiterate to support my ideas.
We know that the early '07s and below do not work with the facelift CC because the flaps and motors in the AC system are different. According to the Bentley manual, this change started in May '07. My A3 is a Sept. '06 build, so I have the older system. Specifically, the recirculating flap motor (V113) was phased out, as well as the recirculating position sensor (G143.) These are pins 7 and 8 in the smaller black plug, and pin 6 in the red plug, on the back of the CC unit. All of the other pins are identical. The bit that's got me curious is how the pre-facelift CC units can work on both the older and newer setup. The Bentley manual states that whenever you replace the CC unit, you must perform "Basic Setting for A/C System" and check coding and adaptation in VAS5051. I'm assuming that's how the CC knows whether you have the flap motor V113 or not, and adjusts accordingly. What I'm wondering is if there is some way to make this change on the facelift unit. Since every car that the facelift CC came on has the newer blower system, it makes sense that they are all set for the newer system by default (thus not working with pre-May '07 cars.)
Now, the pins for this extra flap motor are still physically present on the facelift units, and by tracing out the circuits and comparing against the pre-facelift unit, it seems that all of the electronics for those pins are still physically present (as opposed to simply being a dead pin that's not electrically connected to anything.) I've dug through Vag-com hoping to find a way to change the setting. There are only four entries under Basic Settings, none of which are applicable. The adaptation channels are set identically to my pre-facelift CC with one exception: channel 5, which is set to '1' on the old unit, simply does not exist on the new CC. There is no identifying label on this channel, but I did try changing it to '0' on my old CC to test this theory. It made no noticeable difference, and definitely did not make it behave like the facelift CC. No idea what this channel does. The 'Coding' button for the HVAC module is greyed out in Vag-com. The other thing I found interesting is when I go into measuring block 007 for the recirculation flap motor, it says "Not Installed" in green text. This leads me to believe that the software on the facelift CC is at least aware that something is associated with that group. Normally when a channel simply does not exist, it says "ERROR: Unavailable" in red text. Seems promising to me.
So this is where I'm stuck. Does anyone have any bright ideas from here? Could this be hidden in the Security Access menu? Could it be in the non-accessible Coding menu? Can I enable long coding by generating my own label file for Vag-com? Of course, it's possible that the software on the facelift CC is hard-coded to not accept this additional flap motor, but if that's the case then why leave any reference to it at all? As last resort, I may take it to the dealer and have them run the basic setting/adaptation procedure with their VAS tool.
FYI, I have had identical results with the latest official Vag-com release (10.6.4) as well as the beta (11.3.0)
A few other tidbits I've learned the hard way that may help some others- I bought this facelift CC as part of a double DIN conversion. I tried swapping the new CC faceplate onto the old, single DIN CC electronics and backing plate- does not work. I could live with a couple of the LEDs being irregular, but on top of that half of the buttons do not work. They are either too close or too far from the circuit board and do not actually make contact properly with the switch and do not do anything when you press them. Additionally, the 'AUTO' LED does not illuminate when the faceplate is swapped (which we know,) but contrary to what was stated it is not an issue of a wire being too short. The LEDs are surface mounts on the circuit board, so there is no wire, and no good way to extend it to the proper place.
Finally, I did end up swapping the chrome knobs from the facelift CC onto my old CC, however I did it differently than shown on the German site linked above. I don't know if my way was better or not, but I thought I'd share: I did not remove the knob from the chrome ring, I pulled the knob/ring assembly out as one piece. Then from the back of the old CC, I enlarged the four holes where the tabs on the chrome ring snap in (see pic 2 on the German site,) then I ground down the raised plastic channels from the front (pic 6, outlined in red) until they were flush with the surrounding plastic. I used a Dremel with a grinding stone that has a flat top to do this, then an Xacto knife to trim the stray plastic bits leftover from grinding. At this point the knob and ring will clip in perfectly. You must reuse the white plastic spring retainer from the old CC, the new one won't work (although you can reuse either set of springs.) Unfortunately, I scarred my old CC faceplate in the process as my Dremel slipped at one point. If you're going to attempt this, tape up your faceplate first!
