We have the same thing going on with cars , can you tell us if your fix will work on a 2002 Marquis and a 2003 Crown Vic EATC . We think Ford should have a re-call on them or help with the cost but no luck , sounds like everyone that owns a Ford with EATC has the same problem no matter what year or the mileage on them . Ford wants $1000 for a new one witch is bull , have tried to find a good used one but no luck yet . I want to print your post on how to fix it with the pics but can't find on the post how I can do it , so is the a way you can e-mail everything you have on here to my address , bherms128@gmail.com , Where are you located ? would like to fix ours ? do you know anyone in Indianapolis In or Greenfield In that can do it ? .. Do you know where we can find two good used ones ? any more help you can give us will help , Thank you ........
/ quote=Marauder2004;9037626]The Electronic Automatic Temperature Control (EATC) module used in Mercury Marauders, Grand Marquis, Crown Vics, Town Cars, F-series trucks, and numerous other Ford vehicles are essentially the same, with some minor functional and cosmetic differences, but they are the same inside. When the o-rings fail, the default setting allows air to only exit through the defrost vents. This is not the only condition that can cause this problem, but it’s the cause in over 80% of cases when an EATC is involved. If your truck or car has ***** rather than electronic buttons, this is not a solution for you.


These instructions were written by a fellow Mercury Marauder owner who has experienced the failing o-ring syndrome of Ford’s EATC module, so I can’t take credit for it other than some minor editing. I have repaired a few of these and it's pretty easy.
Remove the Electronic Automatic Temperature Control (EATC) module from the dash. The EATC is usually mounted by four screws hidden behind a snap-on trim panel around the face of the module. Once you remove the screws, pull the module outward to get behind the unit to disconnect the vacuum and electrical connectors at the back of the module and remove the module from the dash.
Replacing the o-rings requires disassembly of the solenoids, but that's really not that hard to do, if you have reasonably good mechanical aptitude. But first, make sure they hold vacuum when not energized. Connect a hose to the center vacuum port (where the black vacuum tube was connected) and suck it.
It should hold vacuum. If it doesn't, the following fix probably isn't for you.
I used o-rings from McMaster Carr. You can get 100 for about $5, part number 936K12, silicon #007 o-rings. You will only need four. If you need some you can pm me for my address and send me a self addressed stamped envelope and I’ll send you some.

The solenoid assembly comes off the EATC module by unscrewing the two T-20 Torx screws on the backside of the module. Pivot the rear of the assembly up, and disengage the tabs at the front of the module. Disconnect the solenoid connector.


Lay the solenoid assembly on it's back, and remove the 10 screws holding the solenoids and plenum strap to the plastic frame.


At the wiring end of each solenoid, you'll see two metal tabs folded over, that hold the solenoid coil and armature to the solenoid frame. Straighten these tabs and then carefully pull out the armature, while watching you don't lose the spring or plunger that are inside. Note the o-ring on the armature. That's what we're after.


Next, slide the coil off the end of the plenum tube, and then pinch the ends of the solenoid frame together to release it from the plenum. Once the solenoid is all apart, fit the armature back into the end of the plenum tube to check that the o-ring has a good snug fit. If it does, clean the inside of the tube, and reassemble the solenoid. You can replace the o-ring if you like, but if it fits well, there's no need.


Make sure you pay attention to the screw flanges on the solenoid frame. Pinch the end of the frame together to fit it back onto the plenum. The spacer that goes at the plenum end of the solenoid has the inside diameter undercut, and four grooves. The undercut end goes toward the plenum, and you'll see four ribs at the base of the plenum tube that mate with the four grooves in the spacer.

The armature slides back on next, followed by the plunger, and then the spring. (The flat end of the plunger goes into the hole first, if you missed how it came out.) Use a bit of dielectric grease on the o-ring, (I used Nylog) but do not use any oil or anything on the plunger. Make sure the tip of the armature where the plunger seals against it, is clean and shiny. Don't get any dielectric grease on the
tip of the armature. Clean and dry is what you want here. Slide the armature back into the end of the solenoid, and while pressing everything back together, fold the metal tabs back over.

Repeat this for each of the four solenoids.
You might be tempted to only replace the O-ring on the leaking solenoid only, and leave it at that. Don't- do all four while you’re there![/quote]

 

You have mail.

 

Dont be afraid to tear it apart....its already broken anyway. I did mine and only took me about 10 minutes its easier than it appears. Once you take the unit apart you will understand the pics even better......just wanted to encourage anyone who was afraid to try this.....mine works perfect thanks again everyone

 

I have a 2002 F150 King Ranch that I just bought. It had the AC issue you guys have discussed here. The AC issue caused the price of the truck to drop significantly. I was able to fix it for $2.59. Thanks guys!

 

Repaired my AC control panel with the instructions, and everything works great. Thanks for the hlep

 

Just did this on my 2000 Expedition last night, I think it took all of 15 minutes to change the 4 o-rings, what a difference in sealing ability. I put it back together and it now works GREAT. Mine was a little different though, as my solenoids and plenum are spot welded on a metal frame, and not screwed to a plastic one.

 

Timing to resurrect this thread is great. My 2003 F-150 w/ auto a/c controls started blowing to defrost when on max a/c. Called around town and was referred to a local mechanic that does a ton of these repairs for ~ $150. Found this thread and decided to give it a try today. I invested about 2 hrs, 2 cold beverages, and $2 in O-rings. Test results show the a/c is back to normal. I went with the 008 O-rings. Biggest hold up was removing the dash trim because I was concerned about breaking it. Got the job done on my time without having to leave a vehicle at a shop. Thanks Marauder2004 for the information..

 

I have a '99 F150 XLT with manual A/C controls that's been blowing through the defrost outlets on uphill, and back through the front dash vents on level ground and downhill.

I will check the vacuum lines and reservoir for leaks. BUT, is it possible that the manual control can leak in a similar way to the automatic control? If so, is it rebuild-able?

Thanks,
Lou

 

This problem is caused by a loss of vacuum, when the o-rings get brittle they begin to leak. Similar situations can be caused by a vacuum leak somewhere in the lines. Check to see if your manual controls use cables or vacuum solenoids connected to the control by a vacuum line to control the dampers inside the hvac box. (You have vacuum controls if there are vacuum lines connected to the rear of your controls.) If yours are operated by vacuum you probably have a leak somewhere. This problem shows up during acceleration and hill climbing because the engine's vacuum drops at these times and (due to a leak in the system) there's not enough vacuum to keep the solenoids and dampers in the correct position, thus the system defaults to defrost.

 

I want to thank Blue Tick for the AC post, I have been riding around in 110 degree weather with my AC coming out of the Defrost. THANK YOU VERY MUCH you have saved me a ton of money and time. All I had to do was replace the gasket. You are the best and I thank you.

 

Thank you to Marauder2004, I think you posted the instructions to fix my problem. THANK YOU,THANK YOU, THANK YOU.

 

Well, changed out the o-rings about 3 months ago, worked great. Now the problem has came back I think i might of used the wrong o-rings. I used the #36 available at lowes. Going to order the recommended #007 o-rings on-line and try it again. Hopefully that is the problem

 

I used #007 and had the problem return. Next time I used the #008 and a little mobile 1 oil and never had the problem again.

You can get the o-rings at a local hydraulic hose place if you don't want to order.

 

Thanks for the tip. I will give that a try.

 

I just did this in 1hr and it works awesome now Thank You Thank You Thank you