Only defrosters....Lightly

[LoquetusofBorg]

I would like to talk to anyone whom understands EATC unit. I have read all the post I could on here. I have a 98 sport and put a 98 limited wire harness under the dash and a wire harness in the engine bay. I have all blower speeds so I think the blower control module is good. Ran a diagnostic on the eatc head unit all is good with an 888. but I can not for the life of me figure out with the rest of the controls, like floor, defrost, vents and the rest of them. I have put a new blend door in when I had the dash out along with a new plenum. I have not checked to see if that works because it is so hot here I just did not want to find out if the blend door worked. My question is what controls the shifting of the vents, floors, defrost etc.. I cant any of the different settings to work. It only lightly comes out the defrosters. I here the fan blowing but just trickling out the top. I have checked the relay under the hood on the drivers side but not the under air box one, and I am not sure those relays are for vent switching just blower speeds. anyone have this problem withe the eatc unit. Thanks.
Robert

 

[koda2000]

From what I've seen and read on the EATC unit, there are tiny solenoid valves inside. These valve direct vacuum to the various vacuum motors (I believe there are 4 of them IIRC) that control air flow direction by opening/closing doors in the heater plenum. The problem that can occur is that the tiny solenoid valves inside the EATC unit have tiny O-ring seals that can leak with age. If this happens vacuum is not going to work the door motors very well (if at all). Not all problems with the EATC can be found using the diagnostic mode, which only appears to check the electronics of the unit.

Where did you get your EATC control unit from? There's a company that will exchange or rebuild your unit for around $100. Personally I'm not a big fan of the automatic HVAC controls, though most of my vehicles have them.They may look cool, but I find the manual controls more to my liking.

 

[LoquetusofBorg]

Thanks Koda2000, I thought the same thing and went out and replaced those 4 little pumps with some other ones I had laying around then did a diagnostic and the same thing, 888. The problem with my solenoid is they are spot welded and I would have to destroy them to put the new seals in, I have the new seals. I bought them after doing research on them and thought "what an easy fix" but all those easy fixes are for the units that are screwed in, I can't even find a test for those units that I could do. When this all started I only researched How to put the eatc in and what it would take. It was not till after I was committed to this that I see how unreliable they are. If I had to do it over I would have skipped the eatc part of all I have done to this rig to keep the simple set of controls. I bought the eatc unit at a garage sale in a near by town and he had many explorers and I bought many things from him. The other eatc unit I pulled from a 98 limited, the one from the garage sale was from a 97 or 96. I disassembled the 97/96 to get the blue digital read out then swapped it out for the green digital read out in the 98, not the entire face plate mind you, just the read out. They were the same connections for the read out. I tried the 97/96 first in my rig and it kept blowing fuses, I could here them pop.
Do you have the website or a number I could call of this place that fixes them?
Do I send the entire unit in or just the pumps?
Thank you for your help.
Robert

 

[LoquetusofBorg]

Also Koda what would make it only trickle out the top,(defroster). seems I am missing all that fan pressure somewhere.

 

[koda2000]

Also Koda what would make it only trickle out the top,(defroster). seems I am missing all that fan pressure somewhere.

The default on the manual control version when vacuum is lost/low is to blow out the defroster vents. I assume the same may be true with the automatic controls. Perhaps you have some vacuum so you're not getting full force out the defroster vents, but that's just a guess.

One thing I learned on our first Explorer is that even a tiny vacuum leak is enough to cause air directional problems. A previous owner had blocked an unused vacuum line with a screw. This screw caused enough of a leak that under hard acceleration, or when climbing a hill the air would switch to the defroster vents, switching back once adequate vacuum was restored.

 

[LoquetusofBorg]

That is a good guess. I was not even thinking of vacuum, the lines are 18 years old, I should have checked those first. I should take my rig out for a test drive and see what happens at 55-60 mph, just to check for vacuum and what it will do. It is a good thing that it defaults to defrost as that is the the best place in the rain and cold. With your help we will make it right. I will take it out for a drive tomorrow and post the results. Thanks again for your help.
Robert

 

[koda2000]

Engine vacuum decreases under load, driving at 55-60 MPH does not necessarily mean the vacuum is going to be high or low. Vacuum is highest at idle and lowest under a load.

 

[LoquetusofBorg]

Thank you, but I will test anyway just to sooth my brain. I also have spent a lot of time and ran across this video for everybody that has the welded solenoid vacuum pumps, have not watched it yet but plan to after I am done. here is the link :
Robert

 

[koda2000]

I watched the video. Yes, those are the O-rings that can cause problems. I don't know if your EATC unit would be any easier to take apart than the one in the video. Not that difficult to remove and investigate though, actually easier than in the F150 video.

Our '00 Mountaineer's air directional controls have never worked since we bought it over 4 years ago. It mostly just blows air out of everywhere with decent main vent air flow on A/C Max, but not great.

Despite having replaced the EATC unit last Fall, with a used ebay unit (because the original stopped working the blend door actuator) my air directional control is still pretty much non-existent also. Maybe I'll take my old EATC apart to see how difficult it is to replace the O-rings. If I'm successful, I'll try replacing the O-rings in the current unit.

 

[LoquetusofBorg]

I have one from 98 and one from a 97/96 and they are both the same welded vacuum pumps. I will fix one and see how that goes, goes good I will fix the other for a spare. Thank Koda2000.
Robert

 

[koda2000]

I have one from 98 and one from a 97/96 and they are both the same welded vacuum pumps. I will fix one and see how that goes, goes good I will fix the other for a spare. Thank Koda2000.
Robert

Let me know how it goes. It could be a while before I mess with mine. I have more urgent mechanical problems to deal with right now.

 

[LoquetusofBorg]

Will do..

 

[LoquetusofBorg]

Well fixed the vacuum pump ad "wa la" nothing. It was a very easy fix , just drill the spot welds out by flipping it upside down and the hole is almost drilled for you. I then changed the "O" rings and put it back together and soldered it back together, not sure that will hold so I will get some tiny bolts and nuts and do it that way. I will now have to track down the elusive "globe of 0 pressure" and look at hose's and other fun stuff, man this is a lot of work for air and heat to come out the proper holes. EATC is cool looking...........

 

[koda2000]

The globe/reservoir lives in the front of the passenger fender and is bolted to the plastic inner fender. Not much too it. One line from the engine supplies the vacuum and another line out, which leads up to the fire wall. At idle the engine should supply around 19-20 bar (or whatever they call it) of vacuum to the globe.

Do you have a hand-held vacuum pump and/or a vacuum gauge? If you do you can try isolating the globe and see if it holds vacuum. You can also you is to test the vacuum motors in the cabin with the pump. Typically when you have a substantial vacuum leak your idle will be higher than it should be and you might even get an IAC or lean code.

 

[Turdle]

This thread should help you find the components.

http://www.explorerforum.com/forums...ents-a-how-to-what-to-look-for-thread.192842/

 

[LoquetusofBorg]

Good afternoon Koda2000,
Yeah, I don't have a vacuum pump but I will locate and remove the globe and replace with new, if it is not to expensive, thank you for the link, and most likely replace the hose to the globe from both the fire wall and the engine as it would be less work for me that way. Meanwhile I will check under dash on passenger side and see if the re-cerculation valve works, if it doesn't then I think we found the culprit. I have also been reading that manual, when you get time it is a good read. Well when I check out the prices for all the hose and tank are I will post an update. Thanks for all your invaluable help. I have kept all my stock wiring and components if this does not work, I will put it all back to original status with the exception of the under dash harness and just wire the manual controls back in. I have had that dash harness out so much I could probably do blind folded. There is one thing about the explorer that has never been mentioned here, did you know that 98-99 have 2 relay boxes under the hood,(no surprise), and a fuse panel and another relay box under the dash? No one here ever talks about that one. When I could not figure out why I was not getting any power to the fan, (back before the engine bay wire harness), I ran a check on my stock sport wiring and found that the fan control goes to that also, I believe it is the low settings. That relay box is behind the dash of all places. I love my sport but I am getting on in years and I don't think I want to be challenged for everything electronically in the future. The price we pay I guess. Have a great weekend.
Robert

 

[CDW6212R]

Hi Robert, when you swapped out the wiring, did that include the blower motor resistor unit? That's the one outside going into the front near the blower motor. Those are different for the EATC, about $80 new I learned recently.

The 96/97 EATC is designed differently inside versus the 98-01 Explorer EATC. You cannot swap those, which is why you evidently blew a fuse or something. I want the blue display, and I bought an extra 96/97 unit to see about swapping the front face section.

 

[LoquetusofBorg]

Hi CDW6212R, yes, I replaced everything under the hood because the pin out locations for the heat and air that come to the firewall from the dash are in different locations then that of the sport engine bay harness, which was funny as everything else was spot on the same, thanks ford for the consistencies. As far as the blue face digital read out you can swap those out for the green ones just don't us the main board as you will here the fuses pop. That part of the eatc works great and looks so much better then the green. The thing about the face swap is that you have to take only the digital read out and not the face it is plugged into. It is simple to follow the circuits to see, well at least mine, were the same. If you try to use any of the other components like the board or that face plat that the digital read out is attached to, you will pop a fuse. I know this because I had plenty of fuses and I wanted that blue readout so bad that experimented till it did not pop anymore and has worked for me to this date. I could put the green digital back and see if that would change anything, I mean you could be right. Just because it doesn't pop a fuse anymore doesn't mean it works and I never thought of that and that is a free fix for me by just pulling the unit out and returning it to stock, I will do that on Sunday and let you know, but as for right now the temp goes up and down, fan does to, rear fan works great and shuts off also. Let you know soon. Thank you for your incite.
Robert

 

[LoquetusofBorg]

CORRECTION... Just disconnected the electronics from the face plate and used the face only! not the digital read out. as the face plate on the 98 was the same as the 96/97 , at least the buttons anyway, .except the color of the plate itself. I just got the spare out and took it apart and that is what I did. Sorry everyone, I have done so much to this thing in the last 9 months I did not remember it right. Were straight now.
Robert

 

[koda2000]

I guess you haven't found the 3rd relay box yet? The one under the air cleaner box. That's not counting all the relays in the cargo/jack storage area.

I spent this afternoon tearing apart the rear diff on my '01 Sport Trac and sourcing the parts to repair it, so no time for reading until that's back on the road.