I have a 94 c220 the air from the center vent goes away the moment I put the car into drive or reverse and if I put it back and hold alittle gas is starts to blow, also if I am in park but turn on the recirc button the center air goes away. While driving under acceleration it seems as if the fan slows down and not much air is coming out. Checked for leaks and had the vacume control block replaced but still no good. Any ideas?

Either leaks in the recric air vacuum diaphram, OR in the sourse vacuum manifold.

IF you push the {EC} button will the center flap re-open?

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MERCEDES Benz Master Guild Technician (6 TIMES)
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MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Yes when the EC button is pushed then the center flap opens. Started the car today in the heat of the day. The center flap stayed closed in the A/C mode, sometimes if I give a little RPM like 1200 then the flap opens up, but soon as I put it into REV or Drive it closes. You mentioned the source vacume supply, can you piont me in the right direction for this? Also thanks for the help!

Try this: Resetting EC/controller - Turn ignition on. Set temp on high. Turn off ignition. Press and hold Rest. Turn ignition on. You should see --P or 00P. Wait five seconds or so. Restart/turn on ignition. This sometimes cures the EC stuck problem. It didn't get my compressor to fire, but it did reset my controller. Michael

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Michael
Southern California/Santa Monica
1986 MB 190D 2.5, 5 Speed Black and Palomino "Mordechai"
1985 Porsche 928S (32V), 5 Speed
1980 Porsche 928 (16V), 5 Speed