I'm trying to help my friend (really) diagnose and fix a climate control issue with his newly acquired '96 E300D. Here in St Louis, the temps are hovering around 100F, coupled with 300% relative humidity (a joke).

Anyway, when he starts the car and begins driving, the A/C works pretty well, cold air out the center vents and side vents. After a few moments, however, I can hear some squeaky sound from deep in the dash, which seems to be related to door flappers, or CC control valves of some kind. A moment or so later, the cold air no longer comes out of the center vents, but is directed to the defrost vents at the base of the windshield instead. The side vents continue to put out some cold air.

No amount of jiggling, turning off and on, or fiddling with the controls will get cold air to come back to the center vents.

All of my previous experience is with W201's and W116's, which all use vacuum actuators to open and close the CC vent doors. From what I understand, the W210 is controlled by electrical servos and solenoids.

Can anyone describe the most likely cause for this condition (cold air out the defroster ducts, but not the center vents)? I have searched the W210 Climate Control threads, but haven't seen this particular issue described.

Thanks,

SteveM.

__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

I need the VIN# to answer this one.


.

__________________
ASE Master Mechanic
https://whunter.carrd.co/

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
2003 Volvo V70

https://www.boldegoist.com/

The VIN is WDBJF20F8TJ019055

Steve.

__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

element, defroster flap
MB# 2028000175

element, air scoop actuator
MB# 2028000675

element, right tempering flap
MB# 2028001575

element, defroster flap
MB# 2028000175

element, legroom flap
MB# 2028000275

element, fresh air/circulating air
MB# 2028000575

Attached Thumbnails

 

In addition to the normal AC actual values and error codes that are accesed via the CCU, there is a flap test that can be run also.

Use advanced search for "SteveBFL and Import Auto Climate Control Unit" or similar to pull up an article he wrote covering all of the above.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Mercedes-Benz A/C Control Diagnostics
http://www.continentalimports.com/ser_ic60046.html

Thanks for the links guys. I'll read through the diagnostics and have my friend do so also. These W210's are more sophisticated than the earlier models, but the "Mercedes Way" of doing things doesn't change all that much. I'm confident that he will be able to get his climate control issues taken care of. At this point, I'm hoping that we won't have to remove the entire dash to fix the issues.

SteveM.

__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner

Did you guys ever come up with a solution to the problem? I have a 98 model that is doing the same thing.