Stuck in defrost position, assume it is actuator which may be the white plastic object to left of glove box when glove door is dropped. Or it could be vacuum hose/motor leak, if a vacuum also controls blend door. Looking for what could be problem. Will not pull dash no matter what.

Any help greatly appreciated

Lack of vacuum going to the blend door. Defrost goes on by default when the vacuum to the blend door is not there. Check hoses on intake and vacuum motor.