Mercedes-Benz 190E 2.3 1987 Owner's Manual page 29

0 Press for fresh air ventilation or air conditioning.
For taking in fresh air or during air conditioner operation,
the air is directed to outlets (5) and (7). Adjust the air flow
with levers (6) and (8) respectively as desired.
1 Off.
In this setting, the Tempmatic Climate Control System is
shut off, including the fresh air supply to the interior of the
car. Do not drive the vehicle with this setting for long peri­
ods with windows and sliding roof closed since the vehic­
le's normal interior airflow will be disrupted.