We have a 2004 grand marquis. The problem is that the air conditioning won''t come out the vents, only the defrost, no matter what we do. But, at least we had air conditioning. Now, though, I turned on the heat on a cold night and the air conditioning came out the defroster, the heat came out the vents. And there was no way to shut it off. Then, the air conditioning quit entirely and now we only have heat and still there is no way to shut it off. We''ve been to the local Ford garage and they don''t know what is going on. We think it has to be the electronics, but they don''t think so.


Anyone have any ideas?


Thanks

Yes.. It sounds like the temperature blend door actuator. Thisd door switches the air from the floor,vent to defrost.


Now the other problem. It sounds like the control unit for the ac/heat went out. is this a digital unit or does it have knobs to adjust the temp and ac settings?. It sounds like you have a digital one from the way it is acting.if so the entire unit will have to be replaced. This is probably what caused the problem in the first place. The actuator blend door is probably fine because now the unit is not working. This is why I think it is the unit that controls the temperature.


Is the a/c compressor working? I am just making sure that the door is not shut and the compressor is just not being able to push the air thriough. Loo under the hood at the a/c compressot with the unit switched to a/c max. the compressor should be turning on and off. If it is then the door is definately the problem. If not then I would go with canging the temp control unit that you use to set the temp. Get a used one from a junkyard or ebay. These units are about 400-600 dollars brand new. A good used one from a dammaged vehicle should only be around 50 bucks.


Good luck and let us know what you are going to do...The first thing is find a new dealer!

Jason Sereiko-





Thanks a bunch for the tips on the 2004 Mercury... you know, we can''t find a used part for that in the United States... it has automatice temperature control, all the used ones don''t... Anyway, we took the chance and took it out, cleaned all the contacts and checked it with a meter.. couldn''t find anything wrong, so we put it back in.. We now have air again... but again only from the defrosters and the floor- at the same time LOL... But, as it''s 90 degrees, we''re not complaining right now.


Thanks for the information and we''ll keep look for a replacement. As for the Temperature Blend door actuator, we''ve messed with it before, and won''t try anything with it now until its cooler, we can''t take the chance on the air going out again.

My grandpa is having the same problem with his Grand Marquis not blowing
through the vents and only through the defrost.

Where can I find a more detailed account of what is going on, and where this
door actuator is?

go to your dealer. ask them for a print out of the exploded view of this part. go during the week when it is not busy. you will have to go to the parts counter and ask them for it. it is free

hollyjc


I am glad it is working. Thanks for letting us know and good job on fixing it!

Misdirected air flow from vents
 

I found that the source of my issue on a 2007 Grand Marquis with the same symptoms was (relatively) easily solved.

First - I checked for proper vacuum by following the test on the following link (Thanks Sparky!!)

http://www.sparkys-answers.com/2012/...-will-not.html

Once I confirmed that there were no vacuum leaks and I could test all vent functions as described in this procedure, then I set about replacing the o-rings as mentioned elsewhere on this forum!

My Wife thinks I'm a hero! 2hrs labor, $2.50 in o-rings, vs. the ~$800 the dealer wanted to do this repair.

Regards,

Wally