I've read the post about the blend door actuator and heating and AC. I think I have a different problem though.

I have a 03 Excursion 6.0L Diesel. My panel heat/AC blows fine but I can not get any defroster air movement. When I manually move the plunger, air is cut to the panel and still does not come out of the defroster vents.

Any thoughts? Is it the actuator or something else? I need a defroster here in WI..

Thanks for the help.

 

There is a vacuum pump under that hood that first has to supply vacuum to the climate control to operate the vacuum motors that control the airflow. Check it first.

If other positions work and you can somewhat change them, then you either have a control head or a vacuum motor or vacuum line problem. IIRC, the vacuum motor for floor/vent/defrost is on the left side of the plenum above the gas pedal. Look for the one with three vacuum lines on it.

If you have the electronic control head, those are known for having internal o-rings fail.



The blend door only controls the temperature of the air by admitting or bypassing airflow through or around the heater core. It has nothing to do with where the air comes out, only its temperature. It is electrically operated.

 

Thanks for the info projectSHO89. I will check out the vac line and go from there.

 

I think a loss of vacuum puts it in full defrost mode. Are you saying you can switch from floor to panel but not to defrost? If that is the case either plugged or disconnected defrost hose.

 

All of the heat or AC comes out of the panel vents and nowhere else. There is no problem with the temperature. I have heat and AC. It is just that the air blows from the dash vents only and not the defroster.

 

Which control head do you have?

 

I wasn't talking about temperature but locations of air flow. I was thinking a vacuum leak would put it on full defrost ( window vent ) mode.

 

It is not a supplyvacuum leak nor an issue with the vacuum pump.

Which control head do you have?

 

Did the 03 6.0L come with both manual (****) and auto climate control options?