ATC Problems

Page Revised: 10 May 2019


Automatic Temperature Control (ATC)


Article by
Eric Dess

If your Cougar is equipped with automatic temperature control (ATC, also known as electronic climate control, or ECC), you know that the system usually performs quite well. The Ford ATC system was designed to make the interior temperature of the car more automatic, meaning less fidgeting with the controls. It's not that sliding the lever or flicking a switch with a manual system is bad. It's just that ATC is more associated with luxury cars. The down side is that behind the dash, you have the potential for a lot more problems. For example, on a manual system, sliding the temperature lever physically moves a cable from the panel to the blend door. With ATC, that function is controlled electronically via a signal from the head unit to the blend door actuator (servo motor). All brush-style motors will have the eventual degradation and disintegration of the internal brush contacts. So if you've had your car for awhile or plan on keeping it indefinitely, and you have ATC, chances are you're going to run into a problem somewhere down the line. Add the fact that there are lots of electronic sensors both under the dash and in the engine compartment for this system, and you can really have a mess on your hands.

One of the first signs of a problem with the ATC system is the flashing display. The head unit (where you push the buttons) does a self-diagnostic as it's running. If it finds an actuator fault it will flash the display. Fortunately you can test the unit and get the error code yourself:

  1. Make sure the car is sufficiently warm, at least 50 degrees F (10 degrees C).
  2. Push OFF/AUTO and DEFROST at the same time, then press A/C within 2 seconds.
  3. The code will display. This self-test will stop all normal functions of the ATC unit.
  4. Exit the self test by pressing the COOL button.

When you get the code, compare it to this chart:

ATC Error Code Meaning
01 Blend door actuator out of position.
02 Floor/Panel actuator out of position.
03 Panel/Defrost out of position.
04 Outside air/recirculation actuator out of position.
05 Blend actuator over current.
06 Floor/Panel actuator over current.
07 Panel/Defrost actuator over current.
08 Outside air/recirculation actuator over current.
09 No faults found in self-test.
10 If this appears with any other code, ignore it. If it appears alone, it's the same as code 88.
11 Clutch signal low.
12 Sensor string open (NOTE: if the interior of the car is very cold this error may appear. Try warming up the car, shut off the ignition, restart the car, and enter the self test again).
13 Sensor string shorted.
14 Control head unit worn or damaged (unit must be replaced).
15 Blower signal shorted.
88 No faults found in self-test.

Now a code 09 or 88 doesn't necessarily mean that there's nothing wrong with the system; it simply means that the self-test didn't find anything wrong. If you are experiencing a problem and you get either of these two codes, then obviously something's still amiss in the system.

Another problem is getting cold or warm air when you're not supposed to, or getting air out of vents that aren't selected on the head unit. These problems are more often associated with an actuator. When the actuators start to die, they won't fully open or close their respective doors.

If you have no blower motor power at all, try changing the blower controller. This is also a common problem, and changing the controller (or even just the fuse for the controller) usually does the trick.

Now we don't want to ruin your day, but with a good number of these codes, replacing the ATC head unit is commonly the solution to a problem. You cannot buy a new ATC unit from a Ford dealer, so you'll need to find one at a salvage yard or via eBay. Physically changing the unit is not really all that bad.

Finally, there are lots of different tests that you can perform (if you're so inclined) to isolate a problem. There are too many to list here; shop manuals list at least 13 different procedures. A lot of them include measuring voltage between connectors. If you don't want to mess with this system on your own, about your only choice would be to take the car to a Ford dealer, or to a mechanic that knows a lot about the Ford ATC system. This can be quite an expensive repair so be prepared.