2008 6.4 PSD stock, 125K, I had a squeaky belt and I figured it needed to be changed. When I took it in about the same time my A/C quit blowing cold. Ford said it was the compressor and that I leaked all of my Freon and the compressor was causing the squeak and wanted 1700$ to replace the compressor. I didn't like that number so I took it to a very reputable A/C and heating repair shop. They said I had Freon and the compressor was working but not receiving the message from my computer to turn the compressor on. They also said the compressor was working when they hooked it up to direct power source. This company is replacing the belt and tension pulley to stop the squeak. Maybe related but after driving for 20 minutes or so my air would stop blowing out of my vents. After the truck was turned off for a while it would come out of the vents again. Any help is appreciated. Thank you<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>

 

This sound more like a EATC problem. Like the module.

Press the off button and defrost at the same time then press recir within 2 seconds to begin the self test.

Everything will display if no codes. If codes are present..what are they.

 

What kind of reader for the codes? I had advanced run the codes and I used that method but we didn't see anything.

Would disconnecting the battery cables reset the computer? Or would that even help?

 

codes would read on the EATC display if you do the self test.

 

Ok. I did that and another method I found on an EATC website but nothing appeared on the display. Should I be holding those buttons down the entire time?

 

self test as follows:
The EATC module will retrieve only continuous (intermittent) DTCs when carrying out this procedure.

Retrieval of continuous DTCs can be initiated after cycling the ignition switch from OFF to ON. Normal operation of the climate control system stops when retrieving continuous DTCs.
To retrieve continuous DTCs, press the OFF and DEFROST buttons simultaneously and release, then press the recirc button within 2 seconds. All vacuum fluorescent segments will be displayed if there are no continuous DTCs present. Continuous DTCs are indicated by the presence of the Celsius symbol (°C) on the EATC module display. Record all DTCs displayed.
If any DTCs appear, carry out the diagnostic procedure. Refer to the Electronic Manual Temperature Control (EMTC) Module and Electronic Automatic Temperature Control (EATC) Module DTC Chart and follow the ACTION for each DTC given.
If a condition exists but no DTCs appear, GO to Symptom Chart Condition: The EATC System is Inoperative, Intermittent or Incorrect Operation.
To exit and retain all continuous DTCs, press any button except DEFROST. The EATC module will exit the retrieved continuous DTCs mode and retain all continuous DTCs.
To exit and clear all continuous DTCs, press the DEFROST button. The EATC module will exit the retrieve continuous DTCs mode and all continuous DTCs will be cleared.
Always exit the procedure before powering the system down (system turned OFF). Once the procedure is exited, the ignition switch must remain ON for at least 30 seconds to allow the door actuators to automatically recalibrate.
Continuous DTCs will be deleted after 80 ignition switch ON cycles after the intermittent fault occurs.

 

Ok, I got it to work. I pressed the off and defrost and released them and then pressed Auto within 2 seconds. Every possible section in the display stayed illuminated. No codes. Hmmmm.

 

Only other option is probably to get the pcm codes read.

You can try to do a cold boot to the eatc. Just involves un plugging the module.

Turn the key off, unplug for a minute reconnect then turn on a press any button and let it go thru the process and see what it does after that.

 

Thanks Senix, if I get a chance to try that I'll let you know. Otherwise I'm going to have an electrical shop run a diagnostic on the pcm. Thanks again.

 

I tried this method just to see what comes up and I'm getting a "12 55c" flashing. What's the 12?

 

I can't find a 12 code on the charts.

They are all a letter with numbers

 

Below are the codes that I have used.


ELECTRONIC AUTOMATIC TEMPERATURE CONTROL (EATC) MODULE DIAGNOSTIC TROUBLE CODE (DTC) INDEX

DTC EATC code Description

B1249 249 Blend door short/Blend door failure
B1251 1251 A/C in-car temperature sensor open circuit
B1253 1253 A/C in-car temperature sensor short to ground
B1255 1255 A/C ambient temperature sensor open circuit
B1257 1257 A/C ambient temperature sensor short to ground
B1261 1261 A/C solar radiation sensor circuit short to ground
B2416 2416 Recirc door short recirc door failure
U1041 N/A SCP invalid or missing data for function read vehicle speed
U1073 N/A SCP invalid or missing data for engine coolant
U1222 N/A SCP invalid or missing data for interior lamps
U1235 N/A SCP invalid or missing data for displays"

 

those are the only codes I can find as well.