Help with 2012 HVAC drama?

[psproule]

Daughter has a late 2012 built Australian delivered RHD Sportiva" with a 1.4MA and TCT.Includes dual zone climate control, Brembos, turbine wheels, mid spec interior and seems to have the lower suspension spec of the Veloce. It's her daily but it also regularly gets taken on club drives with the Canberra chapter. We "rescued" it from an un-caring owner in Sydney who had let a few things go beyond EOL like engine mounts and cam belt, but once tidied up it's been a great little run around for an 18 year-old. We otherwise own (and fix) Selespeed 147 and 156's, I can and have built engines and transmissions, and I'm a broadcast technologist by background so not afraid of electronics and computers. But I have to admit this one has me beat.

Now I preface this by saying that I've read every thread available on multiple forums and platforms, looked up parts diagrams, have read the operation descriptions, spent a lot of time checking with MultiECU scan, have run servo re-calibrations and so on. Also nearly fired the parts cannon. And despite spending the best part of a day upside down in the foot-well replacing bits and further checking things we are still stuck with the mysterious hot on the left side HVAC issue.

A bit more detail; Checking with MECUScan the temps on the left side were 30+ while the right was 8 to 10 degrees C with demand set to 20 degrees. I found that the usual fault with the recirc flap servo snapping it's actuator leaver had occurred. Have replaced that with the 3D printed part and all is working fine. Also pulled apart the servo and checked all gears, re-lubricated and checked operation before re-fitting and further checking operation on the vehicle. All now good, but also understand this is not the cause of the hot left. The vent position servo and mechanism all checks out fine in MECUScan and visually when operated, and the two mixer flaps also seem to do what they are meant to with the servos working properly. No faults listed in MECUScan either.

As a temporary aid I've looped off the coolant feed at the engine block since summer has hit with a vengeance, but even then temps on the left are still around 23/24 degrees on a 34 degree day - recirc now on.

After breaking out the hole-saw I've removed the left mixer flap servo and checked it for operation. Also dismantled, checked all gears, cleaned the internal position potentiometer and re-lubricated. All appears to function properly.

So at this stage I guess it all points to a broken left mixer flap. With the servo off you can manually move the flap and it feels like I imagine it should - a solid stop at either end and you can feel some weight on it. And you can hear it change airflow slightly in the different positions. But the temp only changes a couple of degrees between the two positions - still in the 20's rather that the 8 to 10 on the right. Before I bite the bullet and try and track down a 1st generation heater box (which does not seem to be available) does anyone have any hints or suggestions? Has anyone actually seen how the mixer flap fails internally? I've seen that the 1750 and JTDm have a repar part available (scroll down) which appears to be a drive spindle / shaft. I imagine that's for fixing a broken flap but it doesn't list for the 1.4MA.

Any or all advice appreciated at this point. This one has me stumped! Pic attached from MECUScan.


Cheers - Pat & Hannah