Dodge 2004 Ram 2500 Owner's Manual page 190

190 UNDERSTANDING YOUR INSTRUMENT PANEL
Temperature Control
Circulation
The cab is designed with features to promote outside air
circulation. There are grilles in the cab back panel. These
are air exhausters that provide the means for regular
exchange of cab air.
The rotary knob at the center
of the control panel controls
the temperature of the inte-
rior air. You can choose your
degree of comfort by rotating
the knob. The coldest tem-
perature setting is to the ex-
treme left (blue region) and
the warmest setting is to the
extreme right (red region) of
the rotation.
Side window demisters direct air flow specifically to the
window glass to help prevent interior fogging of the
glass. They are located in the extreme outside upper
edges of the instrument panel. The demisters also pro-
vide extra air ducts for circulation. They are in operation
whenever the Floor, Mix or Defrost modes are in use. To
remove frost from the side windows, it is best to use the
full defrost mode.
NOTE: When you turn off the engine you may hear a
hissing sound from under the hood for a short period of
time. This is a normal condition that occurs if the air
conditioning system has been on. It is not an indication of
a problem with the air conditioning system.