AC blend door confirmation help...

[Mojave Jack]

Hi Again,
Got to thank this forum that has helped me with so many things...with EB 1997 5.4 4x4 with now removed 4 wheel air suspension and towing package...

After sitting a while (over one year), my front ac won't blow any cool or cold air in the front: my rear air system works as it should, all directions, multiple blower speeds, and varying temperature.

The front works in all speeds, and all panels from defroster with hot air sent correctly from the cooling system, to floor and panel combo, etc. Max ac that has different duct work doesn't blow cold at all either...although all blower speeds and panel directions work as well...

I have replaced the actual temperature knob internals with one from ebay, and tried to get a reading on the old one from .5 to 4.5 volts, but didn't obtain a reading? So I just changed it, but that didn't make any air cold...

I have also recharged and that made a difference in the rear air coldness? But not any difference in the front...also I checked all fuses related...

I just wanted to check here before I do the infamous "last resort ford blend door fix" dremel into the blower box for blend door access...

Thanks if anyone can add some diagnostic clarity before I begin cutting behind the glove box door....

 

[chucks97expy]

The blend door has an actuator that sits under it. Its the little motor that moves the door from open to close depending on if you want heat or air. I would check this first as it sits rite under the door and you can get to it once you remove the center counsole. As for the blend door, UGH I replaced mine but I did the heater core at the same time. Big job for sure unless your gona go through the glove box and cut it out. Hope this helps

 

[chucks97expy]

Sounds like we have the same exact truck, I've replaced a lot of things on mine. If ya need any help give me a shout

 

[rollinstone]

Just tripped on this. There's a blend door fix hack I've used that's fairly easy and under $20 that I used for my '97 Explorer V8 AWD 5.0L...might work for Expys.

Basically, if you've isolated the problem to be a bad blend door (usually the actuator isn't the problem, but the cheap blend door) get a Dremel and make a 3-way cut under the plenum under the glove box so you have a hinged flap. If your blend door is bad it will drop out when you pull down on the flap you've created. It's OK to cut the whole bottom out, but a 3-sided cut will do. RockAuto.com sells blend door replacement kits for about $20. Snap the new blend door in place (trust me, it must snap into place where the old one dropped out at the actuator housing), then tape the flap back into place so the bottom of the blend door is seated. I use Gorilla tape...anything else might get soft when you're running high heat and the flap will come loose. Some use epoxy to seal the flap, but I like the tape because if the cheapo blend door even snaps again, it's an easy fix.

 

[71Rcode]

My actuator crapped out about 6 months ago ---you couldn't hear it turning when I changed the manual heat/cool control back and forth. I believe I wrote up my procedure on this forum. Not too bad of a fix... pull the console, cut the airflow plumbing/plenum against the transmission tunnel and remove a couple other components under the dash to get to the actuator.

Make sure you check that before cutting into the plenum. Your blend door could be just fine.

 

[rollinstone]

YES! 71Rcode is right! Check the actuator first! They're pretty sturdy little units, but yeah...don't just go cutting away without checking that unit first.

 

[IMINYOURCHAIR]

Okay, you've isolated the control knob, Good! next you need to check the function of the actuator. that little bugger lives below the hvac plenum and it's shaft is visible in this picture as a little white knob in front of the heater core (left). if it's turning, then you're in for a heck of a time. Here is the problem if everything works up to the actuator.