2015 Freightliner Evolution Tri-PAC problems

I run for a small outfit. Owner put me in a 2015 Freightliner Cascadia Evolution with DD 15. Old Walmart truck. In May, the Tri-PAC would not cool. Took it to service shop in Hubbard, Ohio. They went through it, charged AC system, said there were no leaks and everything was good. Just last week, Tri-PAC will start up, run for a few minutes blowing the fan but when it seems like AC compressor is about to kick in, the blower fan shuts off but Tri-PAC continues to run. If you switch to fan mode the blower fan comes back on but switch it back to AC it will do the same thing. I tried to get into TK dealer in Millbury Ohio twice but they are FCFS and both times they said they didn't have time to look at it. I have been unable to get back near Hubbard. Both Owner and I are fair at wrench turning but we are lost on this. Any ideas? The amber triangle with exclamation mark comes on when the fan shuts off. My setup has an ON/OFF switch on the dash and a control panel in the sleeper with three knobs, Temp, Fan speed, and heat-fan-AC selector