jimisbell
Senior Member
I was having a problem AC. When I turned it on to start it would not blow any air out of the dash vents for about 60 seconds then suddenly the dash vents open and all is well. This may not sound like much of a problem, but when you get into a car that is 130F and turn on the AC, you want instant relief, not 60 seconds of torture while you wait.
Flow of air is NOT the problem. The air begins flowing immediately but the vents are closed on the dash and wont let the air out, you can hear it hissing as it tries to exit a closed "valve". It is instead, blowing on your feet. Pressing the button that opens the vents on the dash that blow into your face, does open the vents. But in the auto position those vents should be open. But it is intermittent so I never know whether it will work or not. It ALWAYS works 1 or two minutes later. Its like an air valve is stuck and pulls itself loose after a bit.
The problem turned out to be that the control head had intermitent connections. A new control head is about $650 from the dealer so if repairable, its worth doing.
So this is how I did the control head repair:
1) Removing the Instrument Cluster Finish Panel and removing the EATC Control Head are very simple. Here are two links to the procedures:
http://www.lincolnforums.com/forums/attachment.php?attachmentid=3685&d=1383621523
http://www.lincolnforums.com/forums/attachment.php?attachmentid=3684&d=1383621373
2) The unit is a black, plastic, box with two sockets on the back where the control cables attach and a front panel with a display and all the switches and buttons that control the environmental systems (heater, AC, and vents).
3) I did not have the luxury of testing different scenarios to determine what had to be done. I received the box with a comment that, "twisting the box makes it intermintent." Watching the mechanic demonstrate it to me showed that the intermitent seemed to be related to the movement of the cables. But if you are doing this from scratch there may be an earlier test to make before diving in head first to resolder the thing. Try moving the cables around gently, or removing them and reinserting them to see if that fixes the problem. If so you might try just spraying some "contact cleaner" from Radio Shack into the sockets and rubbing it around with a tooth brush to remove any corosion then reinserting the cables. If that fixes it you are home free.
4) If not, then the front panel of the box can be removed as it is just held by two screws and then just snaps in place. BUT, be careful when you remove it as it contains all the buttons and switch toggles. If they are all in good condition, there wont be any problems, but if a few plastic tabs are broken, they might spill out all over the place and you will be on your hands and knees looking under the work bench to find them.
5) After removing the front panel you will see that there are two printed circuit boards. The larger one is fastened to the housing with 4 screws that have to be removed so the entire assembly will slide out. The two boards are connected by a couple of ribbon cables....dont stress them!!!
6) Now the hard part is done. You can see that the two back "sockets" are held to the board by about 20 or 30 heavy wires that bend down at right angles and are soldered to the board. These solder joints are constantly under stress by vibration of the cables behind the dash. They will crystilize and crack, making intermitent connections. You need to re-flow the solder on them so they are soft again. A 40 watt, pencil tipped, soldering iron will do this job. 20 Watt doesnt have the capacity to do the job and larger than 40 watt will have too large a tip. You will have to have a tip that will allow heating just ONE connection at a time and be carefull NOT to let solder flow between two connections so that it forms a short. Just touch the hot, wetted with solder, tip to the joint and wait for the solder to flow. Do this repeatedly on each connection. There are also a few LARGE components on the larger board that have heavy wire connections. Flow those also. DONT TOUCH any of the smaller connections or SMT components or you will wish you hadnt. If you have never done any circuit board soldering, get some instruction FIRST, dont screw up this one learning.
7) Reassemble and try it out.
If it worked you saved $650. If not, bite the bullet and spend the $650 at the dealer. Or go on EBAY and take a chance on a used box for about $100. It worked for me and only took 45 minutes so it was well worth the try.
Flow of air is NOT the problem. The air begins flowing immediately but the vents are closed on the dash and wont let the air out, you can hear it hissing as it tries to exit a closed "valve". It is instead, blowing on your feet. Pressing the button that opens the vents on the dash that blow into your face, does open the vents. But in the auto position those vents should be open. But it is intermittent so I never know whether it will work or not. It ALWAYS works 1 or two minutes later. Its like an air valve is stuck and pulls itself loose after a bit.
The problem turned out to be that the control head had intermitent connections. A new control head is about $650 from the dealer so if repairable, its worth doing.
So this is how I did the control head repair:
1) Removing the Instrument Cluster Finish Panel and removing the EATC Control Head are very simple. Here are two links to the procedures:
http://www.lincolnforums.com/forums/attachment.php?attachmentid=3685&d=1383621523
http://www.lincolnforums.com/forums/attachment.php?attachmentid=3684&d=1383621373
2) The unit is a black, plastic, box with two sockets on the back where the control cables attach and a front panel with a display and all the switches and buttons that control the environmental systems (heater, AC, and vents).
3) I did not have the luxury of testing different scenarios to determine what had to be done. I received the box with a comment that, "twisting the box makes it intermintent." Watching the mechanic demonstrate it to me showed that the intermitent seemed to be related to the movement of the cables. But if you are doing this from scratch there may be an earlier test to make before diving in head first to resolder the thing. Try moving the cables around gently, or removing them and reinserting them to see if that fixes the problem. If so you might try just spraying some "contact cleaner" from Radio Shack into the sockets and rubbing it around with a tooth brush to remove any corosion then reinserting the cables. If that fixes it you are home free.
4) If not, then the front panel of the box can be removed as it is just held by two screws and then just snaps in place. BUT, be careful when you remove it as it contains all the buttons and switch toggles. If they are all in good condition, there wont be any problems, but if a few plastic tabs are broken, they might spill out all over the place and you will be on your hands and knees looking under the work bench to find them.
5) After removing the front panel you will see that there are two printed circuit boards. The larger one is fastened to the housing with 4 screws that have to be removed so the entire assembly will slide out. The two boards are connected by a couple of ribbon cables....dont stress them!!!
6) Now the hard part is done. You can see that the two back "sockets" are held to the board by about 20 or 30 heavy wires that bend down at right angles and are soldered to the board. These solder joints are constantly under stress by vibration of the cables behind the dash. They will crystilize and crack, making intermitent connections. You need to re-flow the solder on them so they are soft again. A 40 watt, pencil tipped, soldering iron will do this job. 20 Watt doesnt have the capacity to do the job and larger than 40 watt will have too large a tip. You will have to have a tip that will allow heating just ONE connection at a time and be carefull NOT to let solder flow between two connections so that it forms a short. Just touch the hot, wetted with solder, tip to the joint and wait for the solder to flow. Do this repeatedly on each connection. There are also a few LARGE components on the larger board that have heavy wire connections. Flow those also. DONT TOUCH any of the smaller connections or SMT components or you will wish you hadnt. If you have never done any circuit board soldering, get some instruction FIRST, dont screw up this one learning.
7) Reassemble and try it out.
If it worked you saved $650. If not, bite the bullet and spend the $650 at the dealer. Or go on EBAY and take a chance on a used box for about $100. It worked for me and only took 45 minutes so it was well worth the try.
