Complete failure of C280 air distribution system
 

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.

If the switch-over valve clicks & nothing happens then maybe the vacuum supply is MISSING. Check the green vacuum line to see if you have vacuum there.

Ali,
I have the EXACT same problem! Did you ever get it fixed? What exactly was involved, and how much $$$!!

Thanks

I responded to the other thread too. I found the problem to be the vaccum source line for the climate control that connects to the intake manifold, it had come off, therefore no vacuum supply for the air distribution system. Cost was free:)

W202 from 8/95 on
 

A/C Diag Codes:

For the fault diagnostics:
1) Ignition on: position 1
2) Temp selector wheel: LO
3) within 20 secs, press the REST and DEFROST buttons simultaneously for more than 6 seconds
4) The LED in the RECIRCULATE button flashes and "dl A" appears on the display
5) Press the AUTO button until all DTC's are displayed and recorded.
6) The current faults are displayed first, then the intermittant faults. "END" is displayed when all codes have been displayed.
7) To erase codes, press v and ^ simultaneously for more than 6 seconds. The display will then show "---". Press AUTO to cancel the erase.
8) Turn Ignition to "OFF" to end the test program.

Hope that helps. Check my page (www house below) for a CD or manual that gives all codes.