Defrost Only on 1992 Lumina APV

[scarmack]

Hello
No matter what you want AC, vent or Bilevel the AC or heat only blows out the defrost no where else help me please

Steve

[richtazz]

firts check the vacuum line from the intake to the HVAC system for cracks/disconnected. the system will default to defrost/floor when no vacuum is present. If you have vacuum, then the actuator for the defrost mode is stuck.

[tomcat0813]

check vacuum control valve assy under right hand dash. Check for 12 volts on purple wire if there remove control vlve assy and take off cover . inspect printed circuit to valve body conections.