i have 1993 chevy blazer s10 i changed the heater core ,radiator, thermostat,fan cluch it heats up but no hot air out of vents same with air conditioner i checked all doors and the open when needed i dont know whats next can some one help thank you chevyblazer4x4man

 

Check behind the glove box door. There is an arm the goes to the vent door for heat, when you rotate the heat control **** the arm should move if not then you may have a problem with the arm, motor or connections to the motor moving the door.