HVAC HELP | Ford Explorer Forums - Serious Explorations

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April 26, 2018
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Woodruff SC
City, State
Year, Model & Trim Level
98 explorer 5.0L
Hey guys,
After extensive squinting at page after page of threads going completely off topic, none I've read has helped resolve this problem.
That being said:
99 Mountaineer AWD 5.0L
150k Miles, unmolested dealer serviced

Charged A.C., cold lines, compressor working perectly, EATC, blower switch good, blower works great, No clicking sound from blend door.
If this is the ye ole cut a 3 sided hole and push the door shut and voila issue I have owned 4 previous mounty's and done them all the same. I would be ecstatic to no end to not start hacking at this pristine example of quality craftsmanship .

Thanks for any help guys!

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Check ALL of the vacuum lines.

Mine did that, one of the lines was allowing the vacuum to leak down.

There are some simple things I would do.
You can google what the codes mean, I think they are related to the blend door and or the blend door actuator.
Check the fuse to the EATC, I do not remember which one. I had codes once and pulled and reinserted the fuse and the codes went away.
Access the blend door actuator and make sure it is moving when you go from hot to cold or vice versa. You should be able to hear it or feel it on the top of the actuator. If not check to be sure the electrical connection is connected securely.
Check to be sure you have vacuum going to the all of the dampers controlling air flow. There is a connection near the fuel inertia switch on the passengers side in the right corner floor.

Sounds to me like the actuator may have failed. If all of these things are okay, then it may be the blend door.

I am in the process of chasing a vacuum ghost this morning. Found that I've got plenty at the heater hose valve, but none once inside. Found the grayish/white line coming from under the washer/coolant reservoir had been "rigged" but it was a very poor job. Gonna seal that sucker up and will post results in a few. Thanks guys!

The blend door and/or it's actuator being the issue (maybe even the EATC unit) would explain the A/C not feeling cold, but it doesn't explain the air only coming out of the defrost vents. That is almost certainly vacuum related. Air only coming the defrost vents is the default position when vacuum is lost.

So after chasing a vacuum issue, previous owner apparently crossed the black and gray hoses , blowing from vents now! Small win.
Next issue is I've got ice cold air coming thru the window defrost vents but regular air coming thru the front vents and rear.

Assuming this is a blend door issue and I can't feel or hear the actuator moving.
Any opinions welcome.

The codes would say this is a blend door issue.
EATC Error Codes.JPG

Ran out of daylight.....gonna cut a hole and shut this blend door in the morning . Hopefully this solves it. Has for all 4 previous 2nd gens I've had.

If you actually got access to the top of the electric actuator and you did not hear it energize (there is a motor in it) then it is the electric actuator, not the blend door.

Yeah, I'm not buying that the issue is the blend door, If it were you would not be getting COLD are out of the defroster vents and warmer/not so cold air out of the dash vents. The air all comes from the same place. Depending on the position of the blend door, you either get heated air (air being passed through the heater core) or not. If you're A/C air is to cold it's possible to "blend" in heated air with the cold air by opening the blend door a little, but you'd still get the same temperature air coming out everywhere (defrost, dash and/or floor).

If it’s only coming from the defrost vents, it’s vacuum no blend door related.

I had that happen on my 00 Mountaineer.

It ended up being a pitifully small hole in the hard vacuum line coming from the vacuum ball.

I also rebuilt the 4 solenoids in the EATC.

I have ac that isn’t far off from being like new, now.

And down here in south Florida, which is a suburb of HELL, that’s important.

After straightening out the vacuum line mix up, which was the defrost/dash vent issue, I still didn't have cold in the front vents......

So went with the go to quick fix, cut a 3 sided hole and gave the blend door the ole reach around. Blend door stuck HALFWAY AND wouldn't budge. Removed the faulty DORMAN actuator that had apparently been replaced recently before I bought it. Blend door moved freely then.

Conclusion , I am a motherfudging expert on the matter now lol. Shut blend door, taped her up and BAM instant ice cold deliciousness!

One thing to say about blend door actuators.....MOTORCRAFT, MOTORCRAFT, MOTORCRAFT. Thanks everyone for the help!