Blend door actuator?

Tiny
REDBONE0165
  • MEMBER
  • 2007 FORD CROWN VICTORIA
What causes the ac to blow from the top and bottom vents but not from the front vents?
Friday, August 20th, 2010 AT 4:05 PM

16 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
The mode selection is done through a series of air doors that are operated by vacuum. When there is either a partial or total loss of vacuum, the system will default to either defrost or on some vehicles, heat. Acceleration can also have an effect on the doors for the same reason.

Look under the hood for a small black plastic hose coming through the firewall. Follow it to the vacuum source looking for any breaks, cracks or leaks. Also follow any other lines that branch off because they may go to a vacuum reservoir (storage tank) and a leak there will cause the same problem. Using a vacuum gauge to determine if you have full vacuum at any given point is the best way to find it. You can cut into the line anywhere and splice it back together with a piece of vacuum hose. Find the broken line, you found your problem.
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Friday, August 20th, 2010 AT 4:18 PM
Tiny
REDBONE0165
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We have checked all of that and there are no breaks, cracks or leaks. I was told that it could be the blend door actuator, but am not sure if this would solve the problem. I don't want to guess at the parts, cause I don't have a lot of money to replace parts that doesn't need replacing. Thank you so much for your prompt response!
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Friday, August 20th, 2010 AT 4:40 PM
Tiny
WRENCHTECH
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No, the blend door is for temperature control, not mode control. The mode doors are vacuum controlled.
If no one has had it apart to create a "man made" problem, then it has to be in the vacuum actuators or switching.
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Friday, August 20th, 2010 AT 4:43 PM
Tiny
REDBONE0165
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Thank you so much for your prompt answers! If it is the switching what do I ask for at the parts store? I am ignorant about car parts and wouldn't know what to call it. :) I will ask about both parts, just need to know about the switching part. Again, thank you so much!
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Friday, August 20th, 2010 AT 5:47 PM
Tiny
WRENCHTECH
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I didn't say to replace any parts. Repair isn't always throwing parts at the problem. The problem has to be inspected to find out why it's doing that.
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Friday, August 20th, 2010 AT 5:59 PM
Tiny
BDOGG0070
  • MECHANIC
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He is right about finding the problem before you get the parts BUT most NEWER vehicles have 3 blend door actuators and yes one of those could be the problem or it could be in the climate control. You definately want someone to check it out to seee which it is because all these parts are pricey.
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Friday, August 20th, 2010 AT 6:26 PM
Tiny
WRENCHTECH
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This vehicle only has ONE electric actuator and it controls temperature.
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Friday, August 20th, 2010 AT 6:49 PM
Tiny
REDBONE0165
  • MEMBER
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Ok, thank you both for your help! This is how it all started. My son took the car up to "Pep Boys". They told him it was the "module" and that it needed to be replaced. They would do it for him if he go and buy the part and bring it back to them, BUT my son didn't ask him if that was what the part was actually called. So, when I called the parts store to get this module that's when they gave me this spill about the "blend door actuator" and that this module didn't come up, but the bda (shorten) did. That's why I was confused and wanted to get more info from you to see what exactly this thing is called. Seeing now, this mod could be anything. Again, thank you very much! You ARE most helpful and I do appreciate everything you have told me!
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Friday, August 20th, 2010 AT 7:09 PM
Tiny
WRENCHTECH
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This is from the service manual for that vehicle

AIR DISTRIBUTION AND FILTERING

NOTE: The air distribution system of this vehicle cannot be equipped with a cabin air filter.

There are 2 sources of air available to the air distribution system:

* Outside air
* Recirculated air

Recirculated air is only used during MAX A/C, AUTOMATIC and OFF modes if equipped with EATC, or MAX A/C and OFF if equipped with manual A/C.

Air distribution within the vehicle is determined by the function selector switch position, if equipped with manual A/C. If equipped with EATC, air distribution is controlled by the electronic automatic temperature control system in the AUTOMATIC mode, but it can be overridden by the driver if desired. Airflow control doors are used to direct airflow within the heater air plenum chamber. Vacuum control motors are used to position these airflow control doors.

The air distribution system is designed to provide airflow from the defroster duct when no vacuum is applied to any of the vacuum control motors. This is done to make sure defrost is available in the event of a system vacuum leak.

Air enters the passenger compartment from the:

* instrument panel A/C register.
* floor duct.
* defroster duct.
* side window demisters.

The center panel duct, defroster duct and side window demister hoses are supplied together as a single air distribution assembly.

Passenger compartment air is exhausted from the vehicle through open windows or luggage compartment air vents.
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Friday, August 20th, 2010 AT 7:13 PM
Tiny
WAY2OLD
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Does this vehicle have EATC or manual controls? Eatc is automatic with an electronic control head. Might be what the shop was talkiong about. Or does it have manual controls? Three controls in the dash. One for temperature, one for direction of air and one for fan speed. If EATC, they have "O" rings that seal in the back of it and they will get dry and leak. Now guys, lets get all the information before getting into any jabs at each other.
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Saturday, August 21st, 2010 AT 3:27 PM
Tiny
REDBONE0165
  • MEMBER
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Well, thank you for replying also. It has EATC. But, by the way I took the car over to the dealer and yes it was the EATC that needed to be replaced and I went ahead and had them fix it. OUCH! It was VERY expensive. The part alone cost several hundreds. Thank you again!
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Saturday, August 21st, 2010 AT 3:32 PM
Tiny
REDBONE0165
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UPDATE: Mr Wrenchtech
Thnak you for all your help! I went and had the car repaired today at the dealer and it was the EATC that needed replacing. Of course you know how expensive that was so I need not go any further! Thanks again and I look foward to hearing from you on my next question(s). Lol.
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Saturday, August 21st, 2010 AT 3:42 PM
Tiny
WRENCHTECH
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Glad to hear you got it resolved
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Saturday, August 21st, 2010 AT 4:32 PM
Tiny
APLUS123
  • MEMBER
  • 1 POST
  • 1999 FORD CROWN VICTORIA
  • V8
  • 2WD
  • AUTOMATIC
  • 166,589 MILES
Trying to removemy blend door motor on a 99 ford crown victoria where do I start?
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Tuesday, August 6th, 2019 AT 10:24 AM (Merged)
Tiny
BLUELIGHTNIN6
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See steps attached
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Tuesday, August 6th, 2019 AT 10:24 AM (Merged)
Tiny
FIXITMR
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I found a person who said they changed it thru the glove box. Dont have details yet. Gotta have small hands/tools he said.
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Tuesday, August 6th, 2019 AT 10:24 AM (Merged)

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