For the most part it seems like everything works fine in either heating or cooling modes, but I'm getting random blasts of HOT air from my '01 Exp. (manual HVAC controls) when in VENT or A/C modes. Here is an example, I can be in VENT mode, with the temp dial all the way on BLUE, and I'll receive cool air from the outside. Then about every 5 minutes (or so), I get a 3 second blast of full on HOT air. After that it goes back to cool outside air. Its real anoying. It started out as very brief burts, but the duration is getting longer and longer.

I'd replace the blend door mechanism, but it seems to be moving OK. I'm wondering what all, thats fixable, could be telling the door to open. I saw the suggestion on another post of replacing the pot behind the dial. Any other suggestions of what I could replace? (before its gets to summer here in Georgia)

I guess my next step is also to open up some of the dash and try to watch the blend door movement. Maybe giggle the dial while and try to get it do it. Any other testing suggestions?

 

gonna have to replace the blend door most likely. my 99 EB expy broke in the heat only position last spring - didn't take long for me to get that fixed - lol!
It's a cheap aZZ plastic gear that moves the blend door and it DOES break and from what I gather they break with some regular occurance for Ford owners. the good news it only happens about every 7-10 years from what I gather! Good thing because my mechanic hit me up for $600 bucks, parts were about $250....rest was labor. Big job if you have the center console.

 

What I'm not understanding in everything I've read and what I'm experiencing is, why is the blend door moving? Whats making the blend door move? Why is it NOT stuck in the full heat position ALL the time? Why do I get puffs of hot air? Why am I sometimes able to control the temputure?

 

A posibility is that your blend door is broken and which is actually the shaft that connects to the actuator and it is moving around on you, thus giving you the bursts of hot air. As far as working some of the time it could be that the broken ends are creating enough friction between them to temporaraly work. The shaft is verticle and so this is possible, I changed one on a Windstar that the shaft was horizontal and the door fell closed and kept it from putting out any heat.

 

I'll summarize everything that has happened, leading up to a fix, with two comments.

1) I believe the newer models, mine is an '01, may have a sturdier mechanism. Same design, but a thicker shaft on the motor and on the door. Just an observation from all the things I have seen researching this.

2) This all started up in the winter/spring, and my wife and I could have sworn we were encountering this prob on vent, but we are second guessing ourselves. I had someone diagnose the issue, granted this was into spring/summer, and they evacuated and refilled the refridgerrant. We haven't had the problem since (all summer).

 

I'm going to order this part, and try to install it myself. ANTHING TO SAVE OVER 1K AT THE DEALERSHIP!!! Will keep you posted on the outcome.

 

Saving $1K is always a good thing.

 

So that was back in 2008. I had bought the blend door mechanism from a Ford dealer, then changed my mind. It seemed like a huge task to tear that interior apart from the floor up. Thats when I had a dealer check it out, and they could not reproduce the problem. Neither could I once I had it in there shop. After that summer/fall the problem just fadded away. It seems that the spring (and the fall to a lesser extent) would bring this on, but it would go away by the time Summer would set in. (By summer I mean HOT-lanta, Georgia.) In the fall we were leaning more on the HOT side, and its harder to feel a blast of cooler air, when its blowing hot air.

So now Spring '09 came, and it was less random, more constant, and more aggravating to me. Then the summer came and it was still an issue. With a summer vacation trip looming at the end of July, the possibility of a hot expedition with 3 kids, a wife, and a 9+ hour drive haunted me. I had to do something. I had bought that blend door mechanism from a Ford dealer back in 2008, but I never installed it. Now I had the proper motivation.

It really wasn't that bad. About 3 hours to remove seats, console, door trim, pull back carpet, remove floor venting, air bag ECM, more floor venting stuff, and then the blend door mechanism. About 2 hours to put it all back.

So now its August and we have not seen the problem since I have swapped out that part. I will report back if, and only if, we see it again.

BTW, the vacation was great and everyone was properly cooled for the drive there and back.