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Ford Crown Victoria/Mercury Grand Marquis Climate Control



  • thetazthetaz Posts: 8
    I would love to see a picture of this fix. I have spent over $1200 and it is not fixed yet.
  • These are usually a case of a vacuum leak where the vacuum harness is not tight to the back of the control head. Two 10" twist ties holding the vacuum harness tight to the control head should fix it. You can replace the vacuum harness for $20, but I would still install the twist ties. The would feed through the back if the unit.

    pull the long trim piece covering the control head straight out. Remove the 4 screws on the control head. Remove the 2 torx screws holding the back cover on, so you can feed the tie straps around it.
    Vacuum harness is F5VY-19C827-A, 2 feet long.

    If that doesn't fix it, then look up Gino on ebay, He fixes the internal vacuum leaks in the control head solenoids on an exchange basis.

  • I will post this week.
  • nebula7nebula7 Posts: 3
    I have this problem too except it found out it was my EATC unit because it worked sometimes and sometimes not, then one day it pissed me off so much that I just took it out one day and beat the crap out of it and I heard a loud electric SNAP and it's worked perfect for a week so far, I still plan to replace it with a lifetime warranty though.
  • How do you post a picture/image on this site?
  • I have 2 good pictures of the fix. How do I psot them on this site?

  • nebula7nebula7 Posts: 3
    Yes I thought it was a vacuum problem at first, but turned out to be an EATC module failure, The unit from 1997 I think? to 2009 is complete crap and can't handle the vacuum pressure and fails. I took mine out and beat the crap out of it while it was all still hooked up and I heard a kind of a loud snap like it was electrical or something and it's worked for 2 weeks now perfectly no matter what I do.

    No you don't have to remove the WHOLE dash, just the wood trim piece, I can post pictures sometime of what I did. All you really have to do is pop off the wood piece (starting from the far right) and then it comes off.... After that the screws are visible in which to remove the EATC module, easy as pie, Also a lot of places on ebay give you a new one for $200 with a lifetime warranty. Very good deal if you ask me considering the Dealership wanted $700.00. I will probably do that myself once I return from the Marines.
  • The blower motor speed controller. It provides 20 speeds for the EATC vs 4 for manual system.
  • ten29mten29m Posts: 1
    I have a control head for a 04 GRAND MARQUIS that needs to be rebuilt. Can you please list the Name and address of the guy who rebuilds them in LA. I also live in LA and would like to talk to him. Thanks.
  • thetazthetaz Posts: 8
    Contact this guy. He gets $175 for the unit exchange and it worked for me.
  • My EATC in my 99 Marquis worked fine for one day after buying it then fuse #5 blew. which i pinpointed to my EATC. It keeps blowing fuses if i hook up the display wire (gray connector) to the back of the unit my display and all work but when i hook up the black connector the fuse will blow? Anyone tell me why? And what i could do?
  • Before you replace it, try pushing the vaccum harness against the control head for a better fit at the 5 vacuum hoses. This vacuum harness relaxes over the years and you develop a vacuum leak. 2 tie straps from the hardware store will hold it tight. I posted a picture of the fix here somewhere. The vacuum harness is $25 but still needs the tie straps.
  • could be the blower motor speed controller. has like 20 speeds that vary the voltage to the blower motor.
  • get 2 tie straps to hold the vacuum harness (5 hoses) tight to the back of the control head. I have pics if needed.
  • I have a 2003 Grand Marquis and the blower motor is not working at all. All controlls (heat/vent/ac) were blowing out the defroster vent for approximately one year. Recentlly everything just stopped working. I wasn't getting any wierd noises or other disruptions prior to it going out. Any suggestions on where to start. I'm unemployed and can't take it to a mechanic right now. Can do the work myself with some guidance. i just don't know my way around this car at all. Thanks.
  • Did you ever find a fix for this? I am having the same problem on a 99 LS.
  • I have not found a fix for this yet. Still hoping someone responds with some advice on how to proceed.
  • Hi....i need your help. my pop has a 2003 grand marq. ..has the same issue -air is stuck on defrost. can you send me a pic. got your repair info. thanks.
  • Mr.snorkelbobby, I have the same problem with my 2003 Merc. GM. Is there someway you would provide me with the pics you are referring to. I have very little experience working on things so with your pics I will try to repair my AC problem. Your pics would increase my confidence level on this project. Thank you! Donald
  • I'd like to help those who have problem on their AC being stuck on defrost. A very cheap solution was to replace the o-rings. you can find it here... eatc+today&page=12

  • My mother has a 2002 Mercury Grand Marquis LS. Not only is the clutch for the compressor and the compressor it's self going out, we lost the screen on the Electronic Automatic Temperature Control. The buttons on the EATC light up, however the screen does not work, thus the unit does not work.
    We checked the fuses, pulled the unit and noticed nothing blown or obviously out of place.
    I did read on this forum about soldering some connections under the hood but I didn't catch where to locate that board.
    I have yet to call around to my local junk yards and garages to just replace the device, I'm hoping someone on here knows of an easy fix.
    Thank you for your time!
  • I have what appears to be the same problem with my 2002 Crown Vic... Please send pictures of your fix.
    Thank you.
  • I would also like to see pix of your fix. Have not been able to locate them on this forum.
  • 2003gm2003gm Posts: 1
    I have an 02 GM LS. The fan was working intermittently in the summer. As the weather cooled we turned on the heat and didn't have any. It was blowing cool air out of the vents(no a/c). Now the fan is not working at all. I've read other post and think the fan is probably the fan control module with the bad solder points. I can fix that. My problem now is with the heat. The a/c compressor comes on and off when called for, but no heat comes on no matter how warm the motor gets. Even at freeway speed where you would expect to get at least some warm draft. you only get cool draft. I can hear the dampers working under the dash. Could this be the control unit or could I be lucky and only be a vaccume issue?

    Any help will be appreciated
  • please post the pics or send them to me too...i also have a 2006 grand marquis and the dealer said the problem was in the control head....a vacumm leak. they want 800.00 to replace it but the service manager said to purchase a used one from a local yard.
  • I am seeing a lot of need for a used control module and they are not cheap. My '08 GM was changing from ac vents to defrost vents while accelerating. I used some weedeater gas line to get vacuum directly to the vent control and it worked and for almost free however it is a rig job. Black vacuum to Blue vacuum line on the vacuum harness
    Just happened to run across info on a Cold Boot process that fixed the problem and saved $300.00 to $800.00 depending on whether you put in a used one or let the dealer do it.
    To cold boot which reinitializes and calibrates the vacuum actuators just turn off the ignition, unplug the two wiring harnesses for one minute, reconnect the harnesses and turn on the ignition. Then push any button except off on the module. Wait thirty minutes for the process to complete. It will appear that nothing is happening but just wait. It should be done in thirty minutes just try it and see if it works. Hope you get a success too.

    The woodgrain trim above the module is a clip on I took it off with my fingers. Then four skrews that hold the module. Ease it out just enough to work on.

    Take Care
    George okc
  • ron30096ron30096 Posts: 2
    Last summer I turned on the a/c and 8000 degree heat came out of the dash, being far from home my easy fix was to clamp off the heater hose to the heater core, this worked great and got me home in a/c comfort. this winter I took the clamp off and was able to have heat but had to turn it off when it got too hot. This year I clamped it off again and I have a/c but only at an idle, accelerate and it goes to warm air. The air blows out the vents and does not change to defrost as in other posts. Anyone have any ideas? Me and my car are old and on a fixed income,so any help would be greatly appreciated. Thanks !!!!!!!!!!!!!!!!!!!!!!!
  • re55re55 Posts: 6
    Mine does the same, heater is on all the time. I have been told that it is the blend door actuator motor. I am having my replaced tomorrow. Let you know if that works to fix it. The part is $55.00 at CARQUEST. If your heater blows only through the defroster, it is the A/C Climate Control EATC . I also had this part repaced with a used one from awrecked car,and it fix the problem of only defroster, but it only lasted 1 year and then it went out again. From what I have read is that the EATC last 60,ooo to 85,000 miles mine went out at 70,000 miles. The one I replaced it with was a little newer car so I would say that is why it lasted a year. New they are $650.00. So we took the vacuum hoses and hooked them up to a type of splitter, and I now manually switch from defrost to vent by moving the hoses from one outlet to the other.
  • ginolenaginolena Posts: 2
    edited April 2011
    I was reading this tread and seems like you guys need some help..

    Some of you have different problems and each need personal solution.

    I'm repair shop owner with more than 10 year expirience, and have a degree in electric engineering. Crown Vics and Grand Marquis are our field for more than 12 years.

    I can give you personal answers to your problem and pinpoint exact reason of failure by symptoms. You can contact me using my profile info, or google my name, since Edmunds prohibit posting emails or phone numbers as contact info in the posts and I'm unable to check this board on regular bases.

    So, here are a few tips:

    1. - If you cannot control air speed , stock on low, stock on high, or there is no air at all - than your fan resistor aka fan speed controller is bad! Located on the firewall, engine compartment, just on the right from the heater core. Buy it from dealer, it's about $60 and replace. Do not resaturn contacts on the old one - if it's happened - this resistor was hot and failed! And bad resistor can kill your climate control! (of course, you have to check fuses and fan motor itself to eliminate possibilities first)

    2. - If you cannot switch from hot to cold air or from cold to hot - than your blend door motor acuator is bad! Located on the top of the blend door itself, in the dashboard behind the glove box. (have to pullout complete dashboard on the pass side to replace). Buy it from dealer, it is about $55 and replace. Do not buy used ones, it's not worse it. Also possible - blend door has mechanical issues and stock - inner temp sensor failed or air pass to sensor clogged with dust - climate control failed. But door actuator is most common.

    2. If your vehicle is 95-97 and your a/c compressor does not engaged - your Climate Control need to be repaired/replaced.

    3. - And finally, what people usually complain about:
    - If air blow thru vents and than switch to defrost while you accelerate
    - If air stock on floor or defrost only
    Than your Climate Control (EATC module) is BAD.
    Vacuum leak inside the control. All Ford-Mercury-Lincoln family cars with Electronic Automatic Temperature Control have this issue! From 95 to 2009 - every control has manufacture flow inside. Control need to be rebuild and updated completely to prevent future failure. No "mickie mouse job" as replacing o-rings or switching vacuum pipe is a permanent solution. Most of the time it make your control falling beyond the rebuild point.
    Years ago I figured out what is exactly wrong there and found the way to fix a problem once and forever. Apprx 3,000 controls been rebuilt allready, with less than 1% warranty returns for the last 7 years. So we proudly supply lifetime warranty on our rebuilds. We can rebuild your, if it's still rebuildable or Exchange to one from our stock, that allready rebuilt, tested and ready to go.

    We also rebuild and exchange Light Control Modules (LCM) for Crown Victorias, Grand Marquis and Marauders - all years from 94 to 2009
    As well as ABS Control Modules (small computer on top of the ABS pump) for the above vehicles.
  • dlw1053dlw1053 Posts: 1
    2001 Grand Marquis with Auto Climate Control. AC works fine. No heat and defrost blows only cold. Also fan is on full when system is on and cannot be turned down or off. Any help greatly appreciated.
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