i why does air blow out front vent and not the defrost when in defrost mode? on 1998 Chevrolet S10

i changed the control module. still does the same thing

by in Collinsville, AL on September 14, 2013
2 answers
ANSWER by , September 15, 2013
check fuses, also actuator may be bad
ANSWER by , October 22, 2013
the wiring and the control module