If you have AC and no heat good chance the blender door is stuck that way, it has an electric motor on it, it's a plastic square box on the side of the heat/ac box, I had to replace mine about 5 years ago.
Glad to see everyone finding a cheap fix for this problem. I have replaced dozens of control heads for this issue simply because the dealer cant take the liability if it fails again. I keep hoping they come out with a motorcraft reman on them but they dont even take in the cores, so that is unlikely. I have thought about taking a dozen or so and fixing them and reselling on Ebay but then again all it take is a couple to fail and you look bad. So congrats on the fix and hope they hold up fine.
Thank you Marauder 2004 for the post. I fixed my new [to me] 03 King Ranch for $1.60 in o rings. If I could add one thing which may help some , when I bent the tabs, the foam disintegrated, no matter how careful I was. The foam was just shot. Since it would have taken the skill of a surgeon to replace it, I came up with something different. After cleaning the old foam out, I stuffed a small wad of fiber fill in the cavity. [It's what is used to stuff toys , pillows, sleeping bags ect.] My Jack Russell is always tearing stuff up, so I didn't have to look to far for a bit of the stuff. Seems to be an ok solution. Thanks again.
I had the same issue with my AC defaulting through the defrost and after the dealership diagnosed that my eatc was the culprit, and a $700.00 quote to fix it, I searched this site for solutions. Although Marauder2004's detailed solution was helpful, I didn't have the time or patience to fix it myself. It was hard enough just getting the unit freed from the dash. After removing the plastic dash face-plate, (which conveniently popped off sections of paint), I had to disconnect and pull the radio in order to get behind the eatc module to disconnect it. (My vaccum lines were too short to fully remove the unit from the dash).
I did finally disconnect it and sent it to an ebay guy in Hollywood,FL who repaired it for 75.00 with a lifetime warranty. Everything works perfectly now and I saved $625.00.
Thanks. All of your posts have helped. It pays to research!
I know nothing about cars, but don't have the $$ to bring my car (2007 Mercury Grand Marquis) in to be fixed. So, I took my only day off and researched the problem. Same as everyone else here...no air in the vents only the defrost. Followed Marouder2004 instructions and photos. Purchased the O rings at Advance Auto (had to buy 4 packs as they only carry an assortment package and only 1 per pack fit). Also, purchased dielectric grease, put it all back together and ....IT WORKED!!! THANK YOU Marouder 2004 .....you rock!
Same problem with my 2003 Ford Explorer.It could be a vacuum leak or electrical problem.Newer vehicles may have electronic flow control… If your truck is not equipped with electronic air flow control then it is done by engine vacuum pressure… I am over 99% sure you may have a broken vacuum hose or unplugged vacuum hose…. So Look for vacuum line leak or disconnections.
The air blend door actuator controls the air temparature inside the truck by letting the warm air (from radiator coolant ) to mix with outside temparature.Depending on how warm you like to have during the cold months it will let the hot air from coolant to mix with outside air and get the desired diluted air temparature ( too much technicallll LOLLL) …
Same thing happens for how cold you want for your truck cabin…. Based on the design it will recirculate the cold air from the cabin to keep the air temparature steady most of the time….
Now the problem starts….
If you turn on the A/C and you only get hot air … Possible cause
1.A/c may not have refrigerant or oil or the compressor is not working… Turn the ac on max cool and max spped and pop the hood and see if the compressor is moving…. if the compressor is not moving see a pro….
2. If the compressor is moving then check the a/c refrigerant pressure… if your a/c has a pressure between 28-35 psi while compressor is moving then we will follow the next…
(Some times if your vehicle low in refrigerant then the compressor will be automatically cutt of from power supply by a switch to save the compressor from burning.)….
3. turn off the car and put the key onto the “on “ position and turn the heat on max and look for shattering sound from the dash or clicking noise…
4. If you hear any clicking noise from the dash then … you are screwed big time… The blend door actuator is broken and needs to be replaced… I do not know how to do it since mine is working fine last 9 years , I own the truck for 1.5 years…
To summarise the situation ,
[B]situation 1: air flow from defrost only—>
Depending on the year , make and model …. It will be a vauum leak or if equipped with electronic flow control then that electronic part may start to fail or failed already.or flow obstruction due to dart or …..
Situation 2: I only get hot air no a/c.But a/c has proper refrigerant pressure and compressor is moving(working)….
Now you are completely dinged out… The blend door actuator controls the cabin temparature by allowing the proper mixture of cold / hot air… It actually open an air door to do this…
If that device is broken or stucked in open warm air positon then you know what I am talking about…
You need to find a way to change / replace it….
Situation 3: Cold winter months and no heat
Unless you are unfortunate with a bad heater core replacement the previous issue stays with the The air blend door actuator malfunction.
If the blend door actuator is working fine… still no warm air then you have to look in to heater core to see what is going on… You may back flush the heater core and give it a try or replace it if it is not working after back flush… any ways you have to clean the hoses no matter what you do …
For one way air flow problem ,, vacuum leak from hoses and vacuum reservoir… or unplugged vacuum line or loose vacuum line… and may be faulty electronic vacuum control….
Before you start throwing parts … You need to investigate the cause then buy parts if needed… An experience and honest mechanic will be able to fix this less than book time…
Get alldata or mitchell1 or ford repair subscription and follow the work around . I am sure you are not the only one who has these problems….
Hopefully I may be a help for you …
I am not a mechanic and I do not take any responsibilty of your losses … This is an idea but not a possible solution...
I have a 1999 F350 2WD that is blowing ac through the defrost also. Does it 100% of time. I have read the FAQ's and also the top 4 threads dealing with this issue. I'm still confused about whether the dampers in my truck are controlled by vacuum only, or if also electrically, and if this control **** O-ring problem is a candidate in my truck.
Take it easy on me I am not asking for a lack of effort, I have truly read the older threads and the FAQ and while I started the think I was "getting it" the more I read, the ore I began to get confused.
Never mind. After tinekring with it for days off and on, it's working. Have no clue what I did to get it to work but it's blowing through the vents again after having hooked the hoses back up to the canister and pump. Did this numerous times and so I know they were fully on securely - won't complain though maybe it will last.