Hey all, just registered to say thank you to all those that have posted info on the blend door issues everyone was having. A few weeks ago while running my a/c (I live in Houston and drive a '99 f-150) it suddenly went warm. Then cold again. hmmm. A few days later, I needed heat and had only cold air. Found this forums and you all saved me. Particullarly Alan who posted the instructions on how to take out the dash and fix it. You are a Godsend!! Thank you Thank you Thank you!!!!

Those instructions are perfect and I had the dash out the blend door replaced and back in in about 3.5 hours. For those of you who are a little aprehensive about doing it yourself...DO IT! It is VERY doable. I had my wife read the instructions and write on the plastic baggies for the screws. She was a huge help and that sped up the process. The blend door from Ford was 45 bucks or so. Beats paying a grand to have them do it.

Here's the best part though.....I know why the blend door hinges are breaking. It became very obvious when I tried to put the new one in. The blend door motor actually rotates MORE than the blend door can actually open and close. In other words the door can only swing open and closed about 60 degrees due to the casing the whole heater core sits in, BUT the motor will actually turn about 75 or so degrees thus putting large stress on the door where it hooks to the motor!!! I put the new door in, hooked up the battery and turned the temp **** and watched the door. It was amazing to see it trying to open and close the door more than it could swing. I could see the bottom of the door actually twisting and straining. My remedy to avoid another broken door was to turn the temp **** and watch the door until it was fully open with no stress and closed with no stress and then make small marks next to the **** for the new max cold and max hot locations. For my truck it is actually about 1/4 inch from the actual **** stops. I don't know if a new motor would turn the same distance or what but for me, I will just keep from turning the **** to the full cold or full hot stops.

Sorry for the long post, I will include a few pictures. I hope others will take it on themselves and save some big bucks. If anyone has any questions, I will be glad to try and answer them. Thank you again to all have posted before me.

 

Dumb question, anyone know how to post pictures? Thanks.

 

Hey 737, good info, thanks!

 

if there is any way to put a stopper on the switch itself. Thanks for the info. I drive a 97, does this happen to this year model as well?

 

I reciently bought a 1998 ford f-150 with the 4.6L v8 the a/c when on blows cold for a few miniuts then you hear a thump sound in the dash then just blows hot air?? had the a/c freon checked ok [full] compresor is running fine WHAT could this be ?? could it be the door thing or what ?? I'v replaced the controlls and that didn't help any !!! thanks....

 

That is EXACTLY what my 99 expedition is doing. I checked the rear-air and found that it was blowing cold. I'm suspecting the blend door as well...

 

Both you last two guys have broken blend doors....

 

is there any way to bypass or get this door to manualy be pulled or ??? to get it to the cold air insted of just heat??? i'm only using this truck hear in the summer and DO NOT NEED HEAT11 right now, and could someone tell me where this door is even at?? a photo or??
thanks....

 

The blend door is under the dash and installed in a large plastic case that is the housing for the heater core. The only way to it is to take out the dash. It's made of very flimsy plastic. The door motor rotates WAY too much for the actual travel of the door, hence why there is recuring threads on how to fix the blend door. I believe 100% that it is a design flaw of the motor. There is no other way for this door to break.

It was easier to do than I initially thought. I was a little timid of it, but as I said above it really was a breeze if you have a helper. Get the instructions and dive in. It won't waste more than a day of your life. But, make sure while you have the dash out that you plug the battery in, put the door in (it'll be obvious to you when you have it all apart), and rotate the temp **** to see the limits of the door so that you can mark them on the ****. Otherwise you'll be fixing it again.

 

Im gonna take a wild guess and say that you should be able to put a resistor inline to the blendoor so it will raise the resistance and shut off sooner, i believe the circuit is setup like a window motor is. Where it hits high resistance when at the end of the travel, and it opens a small circuit breaker in the motor.

But if you dont understand what im saying, then forget it....

 

I haven't seen my still working Blend Air Door yet, but I had a similar experience with an electric motor controlled trunk latch that used to over-rotate and catch, not allowing the trunk to stay closed. It's worked perfectly for years now, minus a couple of gear teeth at one end.

 

So you all know, a broken blend door is common on these vehicles, but be aware the blend door motor should also be replaced at the same time. Why? Cause the resistance in the motor is off causing it to over turn? Someone posted they could see the blend door flex as it closed, this is why. The blend door motor is also a common failure part and somewhat easy to replaced because it can be changed with out removing the dash. Hope this helps some of you

 

Guys I need help on where to get my blend door. The dealers around here only want to sell me the whole box for $364.00. Where is every body getting their doors from? please. by the way I'm in northern Ky Ashland area. Boyd co. Ford is no help at all. Thanks Guys

 

I got mine at the local ford dealership...45 bucks. It's just the door and the frame it swings in.

 

which one? i live in houston aswell...