Heater not working?

Does the blower motor work? Does the engine reach normal operating temp? Are the heater hoses hot, where applicable.

Heater problem
2003 Ford Explorer 6 cyl Four Wheel Drive Automatic 98K miles

When I switch from cold air to heat or defrost I hear a clicking sound in my dash to the left of my radio and it stays cold.

Have the blender door checked. It is located near the heater core and sounds like it is sticking.

thankyou I'll have that checked.

Mike

Let me know what you find.