Ok this mystery must be solved.
I can say for 100% certain that the top center blend door motor, that is accessed by removing (or at least unbolting and sliding back) the center console, center stack cover, and nav display (I guess radio if no nav) to get the front screw and through the glove box opening to reach the rear screw, controls passenger side temp blend hot/cold. If it clicks and you can reach up there through the glovebox opening (just push the stop tabs in and it'll flop down), put your hand on it and feel it clicking AND/OR if your passenger is whining because it's blowing hot air when set to LO or cold air when set to HI and won't adjust, that's the one to replace. #11 in the picture below from
Tasca Parts, for a 2013, part #
DL3Z-19E616-A, note it's the exact same for the lower one. Also note this view is from the driver's side front as if you're sitting on the air cleaner, and so the top #11 is placed pretty much in the right spot:
View attachment 164012
Reading the description, it says "With dual zone auto ac, temp", which makes sense, it controls temp by moving the door in there to either allow colder (evap side) or hotter (heater core side) air through. And since it's pictured above and below the heater box I would THINK that the lowermost one that's nearly impossible to get to would control driver's side temp. The post starting on page 2 from
@killswitch engage supports this and it definitely is as pictured, below the heater box.
View attachment 164013
The description for #12 says "With dual zone auto ac, defrost/panel/floor". But where does that little bastard live? The view puts it up by the #8 plenum, which says "Without dual zone ac" so we don't have that. Is it at the far right in this pic, so far driver's side end of the heater box? As some have described as being next to the accelerator pedal?