Blend Door Actuator

I have a 2002 Ford Windstar and was told that I needed to replace the blend door or heat door actuator. When the van started to go up a hill or when the engine pulls a little more like starting out or going up a hill the air on the AC goes from the vent to the defrost and then sometimes to the floor. After changing the actuator it is still doing this. Can anyone tell me how the actuator actually works and what else it might possibly be?

I read that on a different vehicle where someone said that you need to clear the old codes out before the new piece would work. Don't know whether that is true on not.

I also read that there is a vacuum system created inside where the door is located. If the vacuum system has a leak will that create problems with diverting the air out the panel vents?

Sounds more like a vacuum leak. When an engine is under load theres very little vacuum produced. When theres little or no vacuum the HVAC controls default to defrost mode,(federally mandated design). I'd check for a vacuum leak either on the engine,the HVAC vacuum reservoir or any tubing in between.

Ditto.... whereas the blend door is electrical, there are other doors that are vacuum driven.

The "blend door actuator" you replaced behind the radio only controls the temperature blend door which controls the "blend" of hot/cold air.

The ducting selection (defog, dash, underneath) is controlled by vacuum. Look for the little vacuum switch thingy just to the right of the cabin air intake. It's difficult to see/access with the cowling in place. One of the small tubes may just be loose or have come off completely.

Thanks for the tips. Appreciate it.

Check this thread in the forum:

http://www.automotiveforums.com/vbulletin/showthread.php?t=1052185

Hope it helps.

Oscar.

I ended up taking my vehicle in to a real mechanic instead of doing on my own. Found that there was a crack in what he called the vacuum bowl. Works great now! :tongue:

You have to check the vacumm line under the cowl on the passanger side.