Climate control, vents blow hot air

[John Quinn]

I recently purchased a 1996 Explorer Limited, V8, AWD with just 75,000 on it.
The problem (well, one of them) I'm having is that when you either run just the vent, or when the temp setting is met with the A/C on, the vent blows hot air.
Could it be just the door actuator, or should I be looking elsewhere?

 

[koda2000]

I recently purchased a 1996 Explorer Limited, V8, AWD with just 75,000 on it.
The problem (well, one of them) I'm having is that when you either run just the vent, or when the temp setting is met with the A/C on, the vent blows hot air.
Could it be just the door actuator, or should I be looking elsewhere?

Most likely the blend door actuator or a broken blend door. Both issues are quite common.

 

[John Quinn]

Thank you!!

 

[koda2000]

Member @GLOCKer fought this for quite a while. Turned out his blend door was broken. I've had 3 actuators (on 3 different Explorers) go bad. They strip their internal nylon gears, or sometimes they just stop working.

Note; The manual HVAC controls and the EATC controls use different blend door actuators. They look identical but are totally different internally.

If the problem is a broken blend door there is a cheat to replace the door w/out removing the dash.

If your actuator or EATC module is bad you can try running the EATC self test (Google how to do it), which is sometimes helpful.

 

[John Quinn]

Thank you!

 

[GLOCKer]

Yep. I also had an AC compressor going bad so my whole AC system was replaced. Even after that, it was only blowing cold with the hot water bypassed. Bypassing the heater core kept the box from getting the hot air, thus temporarily fixing the blend door issue.

Testing the blend door actuator is pretty easy; just pop it off the heater box, run the the HVAC system through it's extremes, and observe the blend door actuator to see if it's working.

The fix on the broken blend door is a PITA! It was supposed to only take roughly and hour to complete but I found I had issues indexing the blend door actuator to the new replacement blend door. There are a handful of videos on youtube covering the process of hacking up the box to replace the blend door and you may have a better time than I did getting the blend door actuator indexed to the blend door.

 

[lobo411]

When it comes to getting the new blend door inserted (assuming you're using the "cheat" of cutting a hole in the plenum box...which is really the only reasonable way of doing it), it pays to:

1. Use a tiny bit of lube (I used soap) on the plastic bits that need to squeeze into place, and
2. Have small hands, or have a friend who has small hands.

 

[John Quinn]

Thank you all.
I ran the self diagnostic with the key on and got no errors. I can hear the actuator motor turning. For the heck of it I ran the diagnostic with the engine running and got an 030 code.
Is it possible that the sensor in the dash is dying, or is that a false reading because the engine was running?
Also, when the unit is on "Max A/C" or Automatic, I get COLD air for the most part, but when the temperature in the car reaches the setting, it transitions to hot air.

 

[GLOCKer]

Just a FYI, the actuator can still turn but the blend door itself could be broken where the actuator keys into it. So the actuator checks out good on the diagnostic test but the blend door isn't moving .

 

[John Quinn]

Exactly my thought. Do you know how far down the door pin is and what type of plastic it's made of? I'm thinking that it might be possible to place a small amount of epoxy putty on the actuator (with silicone grease on the areas I don't want it to stick to on the actuator) and it will form a bushing that will adhere to the pin on the door.

 

[GLOCKer]

The problem with that is having the door indexed just right. You'd have to get into the box to index the door to match the position of the actuator. At that point you might as well just install the replacement door kit and have it be perfect.

 

[koda2000]

To index the actuator to the door, I place the actuator where it goes and run the temp UP and DN. At some point the "D" shaped post on the actuator should line up with the door and drop in. Note, getting the actuator to spin may require first running the EATC self test to clear error codes.

 

[Hacra]

When i changed my actuator, i used the old broken D shaped post to turn the blend door to "cold" position (i suppose small yet wideish screw driver can be used for this too), then just set the temp cold and the installation was relatively easy after that, if i remember correctly, at hot position for some reason the installation wasn't really possible somehow, at least i couldn't get em lined up properly.

 

[koda2000]

I found the Dorman actuator (which was inexpensive, but has been working fine 7 months to-date) was a little more difficult to install in my '01 EB because the "D" shaft was ever-so-sightly larger than the OE shaft. This required the alignment of the shaft to the blend door socket to be perfect and I had to push the actuator in rather than having it fall into place. If I had it to do over I think I'd just swap the gear I needed from the Dorman part into the OE actuator (assuming I was dealing with a stripped gear). Doing this would have also avoided the sight misalignment of the front screw holes I encountered using the Dorman housing.

I later pulled together my collection of non-working actuators (both EATC and manual versions) and was able to repair the broken OE actuator in our '00 Mountaineer.

 

[masospaghetti]

+1 for cutting the heater box to fix the blend door. A hot knife works well for this and leaves a relatively small incision to patch up when you're done. I used RTV to patch the incision and it's been good for about 8 years now.

 

[donalds]

Dam cutting the box why not just remove the dash

 

[koda2000]

Dam cutting the box why not just remove the dash

Because that's at least a 1/2 day (probably more like a full day) of my life I'd never get back. Besides, if you go that route you're almost guarantied to have a new problem that you created by pinching/pulling wires or vacuum hoses reinstalling the dash. I'm usually a proponent of doing things the "right way", but if I have a broken blend door I'm cutting the heater box with my Dremel. If you have a leaking heater core, that's a different story.

 

[Hacra]

@donalds you seem to be good source of information, next time i do anything i'll ask from you first.

 

[GLOCKer]

With the age of these trucks and the brittleness of the plastics and wires, I wouldn't do the dash removal. I think it quotes as a 16 hour job to fix the blend door that way? I may be wrong though. You have to figure, in that video he started with a stripped dash. The blend door "surgery" with the hacking of the heater bx can take 45 minutes to 3 hours.

 

[donalds]

@donalds you seem to be good source of information, next time i do anything i'll ask from you first.

I'm not the only one