C4 GRAND PICASSO - DUAL ZONE HEATER

[JFK6_6]

Hi guys, I have a C4 1.6 Hdi 2009 with dual zone digital climatization. I have one problem, i can get hot air in those 2 vents located in rear part of T pilar. I have been testing it, the knobs to make more or less wind do not make any difference, even when i mess with dual zone commands in the display as well allowing or not access from passenger to control the knob.
After several tests, I realized that if I setup air to face in the front, i will have small amount of cold air on those rear vents. in the front the air is hot as expected but in the rear not.
I have been searching for some guidance and information online and one thing that popup is the usual problems that citroen has, the low quality plastic for the flaps. And here comes my cry for help, i have no scheme, no idea how can i find these flaps, specially the one that controls hot air for each zone in the car (this is my guess).
Also, I have tried to remove the glove box (lower one) but after removing several screws that thing is still holding strong to the place, and Im afraid im going to break something. (any pointers here are also welcome).
I look forward to any comment. Thanks!

[mickthemaverick]

You may get some pointers from this video:

[JFK6_6]

You may get some pointers from this video:

thank you. what about the lower glove box? is there any video or diagram to remove it? Im asking because i am afraid to pull it out using brut force and in the process break something.