heater making noise and not blowing hot but cold air on 2003 Ford Explorer

everytime i turn on my heater it wont blow heat but cold air, also it makes a clicking noise,but makes no noise when i put on the air.

Asked by for the 2003 Ford Explorer
You almost certainly have a failed temperature blend door actuator. The dash must be accessed to replace it. The tell-tale sign is the clicking noise when trying to change the temperature from where it sits now.

Beware: some of these also had cracks in the heater plenum (the box that has the doors and houses the heater core, etc). These cracks also exhibited a repetitive click noise and would not adjust the temperature. However, replacing the motor does not fix it.

Still, the more common fix is the temperature blend door actuator.
2 answers
either your heater core or thermostat is shot for the heat part, the clicking could be the blowermotor is going or something is sticking on the motor causing it to click