Dodge 2004 HB Durango - Manual (Page 182)

NOTE: There is a difference in temperature between the
upper and lower outlets for added comfort. The warmer
air goes to the floor outlets. This feature gives improved
comfort during sunny but cool conditions.
Heat (Floor)
Outside air flows primarily through the floor out-
lets located under the instrument panel. A small
amount of air is directed through the defrost and side
window demister outlets.
Mix
Outside air flows in equal proportions through the
floor and defroster outlet.
Defrost
Outside air is primarily directed to the windshield
through the defroster outlet located at the base of
the windshield and side window demist outlets.
NOTE: The air conditioning compressor operates in
both Mix and Defrost or a blend of these modes, even if
the A/C button has not been pressed. This dehumidifies
the air to help dry the windshield.
182 INSTRUMENT PANEL AND CONTROLS