Mercedes-Benz 190 E 2.3 Owner's Manual page 25

EU Press for fresh air ventilation or air conditioning.
For taking in fresh air or during air conditioner operation,
the air is directed to outlets (6) and (8). Adjust the air flow
with levers (7) and (9) respectively as desired.
ijH Press to shut off air entry.
Fresh air into the vehicle is shut off. Use this button to
prevent outside odors, or water from car washes from
entering the vehicle's interior, for example. Do not drive the
vehicle with this setting for long periods with windows and
sliding roof closed since the vehicle's normal interior air­
flow will be disrupted.