I seem to be having a somewhat similar issue with my ac. I just bought my 2015 last month, and after about 3 weeks of driving it the ac just started blowing warm air out of nowhere. I was driving down the highway at the time, but when I stopped at the next town I pulled over and restarted the truck. It blew cold for about 5 miles and then was back to warm air for the rest of the day. It doesn't feel like the heater is kicking on, just seems to be pulling air from outside the truck. I had the truck in the dealer for a week only for them to tell me there was nothing wrong with it. The day after I got it back, I started the truck to go to work and no ac. After driving about 5 miles it started blowing cold again and worked all day until that night. It did the exact same thing again later that night. I am taking it back to the dealer tomorrow to try to get the issue resolved. If they get it figured out, I will let you know what they did to fix it. I'm thinking mine is either a problem with the electronic fan under the hood, the compressor, or the blend door. I'm leaning more toward a blend door issue as I have known a few people to have similar issues.

 

 

Well good news! (I Hope) I got my truck back today and so far the ac seems to be working. They said that the wiring harness that plugs into my compressor was cracked, causing it to not have good contact. They replaced the harness and so far all seems good. I am going to drive it around over the next few days and make sure that it continues to work. Hope this helps with your problem!

 

Thank you for following up with what appears to be the fix!

-Rod