Hi, I have a 2003 F150 Lariat 5.4. Since Ive owned this vehicle for only a couple of weeks, the heater has only worked twice. All digital displays work, I can hear the vents all switching when I hit the buttons, but it never blows any air? I tried the self test, got nothing, unplugged the unit etc....nothing.....any ideas?
Thanks
Lil cold in Canada at the moment lol

 

Can you hear the blower run when no air is being pushed?

Even if it was a blend door issue you should get some airflow.

 

have you tried the max speed? typically when a blower resistor goes bad, the high speed function (bypasses the resistor) will still operate.

 

I have a related issue. I have the same truck and was told my control unit was bad. The heat and ac work but the control will only go to defrost and vent. Vacuum seems to be alright. All fan speeds work. I can hear the door moving from vent to defrost. I found a rebuilt unit online and replaced my so called bad one. I have the same problem still. Any help as to what to check next would be appreciated.

 

I hear it switching, do these units even have a resistor?

 

I had a similar issue. I "rebuilt" the inside of the unit with new o-rings.

https://www.f150online.com/forums/hv...buildable.html
So when you spin the fan wheel to high, the blower does something or nothing?

 

I was told in another thread that the models with EATC do not have a resistor.

 

blower motor spins freely...and this unit has a blower control motor, no resistor.