Rear A/c Woes

[rubin110]

hello everyone, i am a relatively new member of the board. i have found this site to be an unbelieveable resource for any x5 owner, but i am having a problem that i havent seen an answer to.

i have a 2000 x5 4.4i

the fan comes on when you turn on the rear air, but nothing
(or so little that i cant feel it)comes out of the vents. i have removed the storage tray in the armrest and also removed the "s" shaped tube that connects to the vents. funny thing is, the air coming out of the lower hose is pretty forcefull. i checked the "s" tube itself and it is free of obstruction. any ideas?

thanks for your help