Complete failure of C280 air distribution system

[Ali Al-Chalabi]

Hello,

I have a 97 C280 that I have recently had the problem of complete failure of the air distribution system. The system has defaulted into the defrost position and will not change.

When I change the air distribution selection on the pushbutton controller, the black box with all the vaccum lines running out of it under the glove box and next to the dust filter clicks, but nothing happens. So, I would assume that the control unit is issueing the command to change the vents, but is unable to open or close anything due to a possible vaccum leak or something.

I have read Steve Brotherton's article on climate control diagnostics where he shows how to pull any fault codes and do an individual flap test of the climate control sytem, but the article shows how to pull the fault codes on an E320 with the dual climate control setup, and would like to know if anyone knows how to do the same thing for the C280 with the single zone climate control.

Thanks for any imput anyone might have, and thank you Steve for the good info listed in the articles. If anyone has any ideas what might be the problem, any input would be greatly appreciated. Everything else in the climate control works perfectly except for the air distribution.

-Thanks and have a great holiday.