what causes the doors in the system to move when you push the buttons to direct the airflow? is it vacuum pressure? how many doors are there in the duct work? Thanks!!!!!!

The a/c controller (pushbutton) sends ground signals to a vacuum switch-over block that sends vacuum to each of the vacuum elements that open the door in the case.

There are 4 vacuum elements & a vacuum controlled heater valve.

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MERCEDES Benz Master Guild Technician (6 TIMES)
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Mercedes Benz Star Technician (2 times)
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27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
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Thanks! Where might this vacuum block be?

Beside the glove box liner, under the right outside A/C outlet.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
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

found it! Thanks!

Where does the vacuum switchover block get it's vacuum supply? The vacuum pump under the rear passenger seat? Or someplace on the engine?

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