In my '06 diesel with climate control I'm trying to figure out why it won't blow cold air and went to the internet to get the procedure to run the EATC diagnostics. Thing is, it wont run. I have the later EATC that has symbols on the face, not words. With the truck on and climate control OFF, I've tried pressing each button together with OFF, followed within 2 seconds by AUTO and it just turns on. Specifically the lower vent symbol plus OFF followed by AUTO and the defrost symbol plus OFF, followed by the AUTO button. Is there something I'm missing or doing wrong? Also, is there a vacuum function controlled by the aux vaccum pump and valves found on the diesel trucks that could cause this malfunction? Thanks!

 

Have you checked the compressor clutch air gap?

 

Yes, and the compressors cycles and blows "slightly" cool air. I have evac'd the system and recharged it. It was a bit low, but now its right on the money. Last night, I discovered another strange thing and started a different post to address the following. So the systems plugging along and the compressor is cycling as it blows it's somewhat cool air, si I pull the plug on the low pressure switch and short the plug.....and nothing changes. The compressor still cycles. I've never seen this so posted looking for advice as to other things that cause the compressor to cycle. Thanks for the response.