my heater only blows warm or cold air on 1996 Dodge Ram 1500

ive replaced the thermostat.flused the rad and the heater core and add new coolant

1 answer
You may be having a problem with the temperature door. It directs airflow though/around the heater core. If the door is not operating properly you will never have warm air from the heater. I would check the fault codes in the A/C control system, and physically inspect the actuator for the door, make sure it is connected and moving when you turn it to full heat or cold.