EATC problem, I tried to search

sallday · #1 (**permalink**) 06-16-2009, 12:36 AM

I have a 2002 SuperCrew with the EATC. Problem is that the a/c will only blow through the defrost BUT when I select vent on the control panel, air immediately blows through the dash vents although without being cool. However, when I press either Max AC or Automatic, the compressor kicks in and it cools, but immediately reverts back to the defrost. I have run the diagnostic and no codes appear. Am i looking at a faulty EATC? Any help you guys can provide wiill be greatly appreciated. Again I tried searching but haven't found a problem quite like mine.

sallday · #2 (**permalink**) 06-19-2009, 05:40 PM

20 views and no responses? Still trying to figure this out.

lsrx101 · #3 (**permalink**) 06-19-2009, 10:51 PM

There have been a few posts recently with identical symptoms. It seems to be a "recently occurring" common problem as these trucks age. I haven't seen a resolution yet, but my hunch is the EATC controller (The control head) itself.
The Controller controls both electrical and vacuum operated portions of the system. Parts of both portions are effected. The only thing they have in common is the controller itself.
Eventually someone with a "broken" one will have to purchase the shop manual and perform the diag steps and post their results. How about you?

sallday · #4 (**permalink**) 06-20-2009, 12:08 AM

Well I am with you in thinking it is probably the control head. I am going to search my local junkyard tomorrow and I'll report if I find one, and if it fixes it.

dstig1 · #5 (**permalink**) 06-21-2009, 01:47 AM

Vacuum problem or the head unit. You need to sort the issue out by testing for vacuum leaks/proper operation of the vacuum motors, and then for proper operation of the head unit.