Citroen Xantia 1999 air vents problems

[Goldfish767]

Hello. This is my first thread here , ive been following other topics around the website. Sorry in advance for my spelling , im doing my best . I recently bought a 1999 citroen xantia 2.0 hdi for cheap. Ive been facing lots of issues that i managed to fix , but the latest one: with the heater blower turned on , air its not going through the ventilation system. However I would use the slider , the air only seems to be coming at 20% power out of the windshield ventilation. Mention* it used to be stuck on front vents , and blew at 100% capacity . Recently i changed the stereo head unit and i tried pushing it back in its place , could that push something in the back and screw the ventilation process? Tomorrow ill try to dissassemble the middle of the interior and see whats behind , but given the fact that im a beginner in this , i would greatly appreciate any suggestions , maybe some of you guys had this issue before . Thank you very much for your time

[Huskyxantia]

Id say if it is a pipe to vent thing then theres something thats not connected to where it needs to go, if you do get into removing pipes , air ducts you can check for any blockages. If its an electrical issue then if i recall the control sliders metal contacts lift then curcuit wont work, if yours isnt that and only pipes then something has become unconnected, your find it whe you dig about, good luck , nice cars them xanitas