Page 2 of 2 FirstFirst 12
Results 16 to 19 of 19

Thread: Defrost Only - Don't think its O-Rings

  1. #16
    Join Date
    Jul 2021
    Location
    Memphis TN
    Posts
    16
    So I got a EATC from a friend, that is confirmed working. With it installed, I still only have defrost.

    I did find the vacuum feed line that runs up by the cowl and no leaks in it that I can see. I unhooked it from the coupler right near the suspension air pump and hooked the mityvac to the line going towards the interior. I was unable to hold a vacuum at all and heard a hiss from around where the line goes into the cowl. My question is, with the car off, should this line hold vacuum?

  2. #17
    Join Date
    Jan 2004
    Location
    Somewhere in the N.C. Triangle
    Age
    65
    Posts
    26,097
    Quote Originally Posted by khamilton1 View Post
    So I got a EATC from a friend, that is confirmed working. With it installed, I still only have defrost.

    I did find the vacuum feed line that runs up by the cowl and no leaks in it that I can see. I unhooked it from the coupler right near the suspension air pump and hooked the mityvac to the line going towards the interior. I was unable to hold a vacuum at all and heard a hiss from around where the line goes into the cowl. My question is, with the car off, should this line hold vacuum?
    You have a vaccum leak. The Ford HVAC system is a "fail-safe" system. A no vaccum condition results in heat and defrost so the windshield stays clear.

    Check the vaccum tree behind the engine, mounted to the firewall and below the cowl.

    Inside, there should be vaccum at the black line going into the EATC.

    Remember these cars are now over 18 years old. With the hot and cold temps under the hood the vaccum lines will start to fail.
    “When you can’t make them see the light, make them feel the heat.”
    Ronald Regan

    "The only way to deal with the Islamic State - these blood thirsty, blood-drunken, terrorists -
    is to kill them, keep on killing them, until you kill the last one, then you kill his pet goat."

    Lt. Colonel Ralph Peters

    “Be polite, be professional, but have a plan to kill everybody you meet.”
    "I come in peace. I didn't bring artillery. But I'm pleading with you, with tears in my eyes, if you **** with me, I'll kill you all"
    General James Mattis




  3. #18
    Join Date
    Jul 2021
    Location
    Memphis TN
    Posts
    16
    Welp. After taking apart the entire vacuum tree at the firewall and testing the check valve in the A/C line, line that goes to the driver side vacuum reservoir, and the black line that goes to the EATC, I confirmed no vacuum leaks. I put it all back together and still defrost only. I decided to unhook the vacuum lines from the back of the EATC and crank it up. I hooked a vacuum gauge to the black line and confirmed it was pulling 20-25... uh... units when the car was running. I jumped this to the blue vacuum line and VOILA, I have air blowing out the dash vents and not defrost. Thank god I don't have to pull the dash for anything.

    and now for the part that i feel dumb for. I hooked it back up to the test EATC i borrowed that i know works.... and everything is good now. I have full vent control again!

    So, this confirms the EATC I had in the car has bad o-rings (surprise, surprise) and I have no idea why it didn't work the first time when I used the test EATC from another car. Unless the check valve was stuck and my vacuum testing on it knocked it loose. Who knows.

    Thanks to everyone that assisted. I'm not a great mechanic, but I'll try anything once lol.

  4. #19
    Join Date
    Nov 2014
    Location
    KC
    Age
    46
    Posts
    3,436
    I’ve had some not work once replaced. Not sure why. Then swapping to another it too doesn’t work. Giving it a few minutes plugged in key off… then works forever.
    The twins2.3 whipple/aluminatorVortech V-2 lots of goodies

    Current marauders
    04 DTR totaled JUST NOW starting to part out 7-21-2021 https://youtu.be/REUxjP1BVpg

    04 Silver Birch Dark Charcoal Hardtop Whipple Supercharger
    04 Silver Birch Dark Charcoal Hardtop V2 Supercharger
    04 Silver Birch Dark Charcoal Converted
    03 DBP Light Flint #122
    03 DBP Dark Charcoal #232
    03 Silver Birch 300b Light Flint Going to fix er up
    03 Black 300a
    04 Silver Birch Dark Charcoal moonroof in the works

    04 Heaton Swapped DTR
    Joe's Wrecked DTR rebuild thread

Page 2 of 2 FirstFirst 12

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. A/C through the floor and defrost
    By SWOOSH in forum Shop Talk
    Replies: 27
    Last Post: 04-29-2009, 01:18 PM
  2. rear defrost
    By 5arnold in forum Community Discussion
    Replies: 7
    Last Post: 10-10-2008, 04:48 AM
  3. A/C thru the defrost...
    By Brian Humphries in forum Shop Talk
    Replies: 3
    Last Post: 05-29-2008, 09:10 PM
  4. Rear Defrost
    By Hauser717 in forum Shop Talk
    Replies: 5
    Last Post: 08-18-2006, 07:37 AM
  5. defrost
    By nexstar7 in forum Shop Talk
    Replies: 5
    Last Post: 12-20-2003, 10:42 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •