Hello newbie here. I truly enjoy this forum and all the information from you experienced mechanics. I recently bought an 300D. Love the car but I cannot get any air flow from the vents at all. The blower motor was bad and I got it fixed but no air flow at all from any vent. The ACC panel seems to work all right as I can feel the AC compressor cycle but no air flow. Can someone point me in the correct direction. I would hate to take this to a stealership ! I have no spare arms or legs.....

What year 300D? While waiting for someone to ponder and respond, go to the bar above and do a seach on climate control. Look for the threads addressing the vacuum switch which in my cars is behind the glove box. The switch provides vacuum to the various pods which open and close the vent flappers. If I have learned correctly, this switching is done by electrical signal in response to what you do at the dask CC panel. I would provide some links for you but I am on my way out.

Welcome aboard.

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.

Go to advanced search and start reading some threads. Start with search terms like ACC, blower, vacuum, etc. In the username box start with LarryBible and/or Stevebfl. Look for other usernames and search terms to use. Post here with your findings, what you test and specific questions.

Does air come out of any vents? Defrost, dash, floor? The flappers that control your airflow are operated by vacuum. Learn to test your vacuum system.

Depending on the body style and model of MB, there may be up to three different electronic modules controlling your climate control and two temperature sensors. The push buttton controller has a number of relays that control a few vacuum pods via some electronic vacuum relays and some other pods are controled by a temperature controller. The temperature of the cabin and heat exchanger are sent to the temperature controler as well as the setting of the temperature wheel. These are used to tell the monovalve to open or close, what speed the blower motor should be (controlled by the blower spped control module), if the fresh air flap should be open/closed, and if the center vents should be open/closed.

I have several problems with my system. My center vents won't open either. The vacuum pod is ok, the vacuum relay is ok. The controller is just not telling it to open. Still working on it....

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Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

Thank you gentlemen for the information. I forgot to add 85 300D. I have checked fuses, vacuum lines all intact up to the firewall, compressor engages, blower motor runs and moves air just no air out the vents. I will do additional searches but I have read a lot on this forum. I believe that I just bought some sun roof grease from one of you. (BrierS) I hope that you have received payment it was mailed.

Do you have air coming out of ANY vent? Defrost? Heat? Side? Center?

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)