 EATC Display Panel Dead
Here's my post on the Ford Powerstroke Diesel Forum regarding the very same problem:
"I have a 2003 Excursion Diesel and just experienced the same problem! The EATC was working fine until I turned the truck off yesterday afternoon. When restarting it I turned the EATC panel off and after starting the truck I attempted to turn the A/C panel on which was totally unresponsive! After checking other Ford EATC Diagnostics on the web, I decided to check the forum and found your post. I just went outside flicked the lights on and off a few times and lo and behold the EATC Display became alive again! Thanks! But do you have any idea what causes that? I am certain that the Ford Dealer will tell me I am nuts, but the truth is, it worked!"
Spoke to Ford Dealer Service Rep
"He said that he had never heard of "such a thing", but then laughed and said if it worked, I guess you do not need your appointment for tomorrow. He did say that he thought that on the newer models that somehow the Light Module was connected to the EATC module and that flicking the lights on 2 or 3 times could possibly reset the EATC Display Panel."
Go flick the lights on/off a few times and then see if the Display comes alive! Try it and see if it works! | 
