I'm with TXiceman I keep fan on HIGH all the time...
Now some bad news. Carrier no longer makes RV Air conditoners NOR do they sell parts.
(TX do you know when they dropped out of the market?) I thought here was a rule they had to sell parts for so many years after they stopped making them but what do I know?
The blower motor went out on my bedroom unit 1.5 weeks ago.. We played Musical Motors (Very easy to remove and replace) and got the more important bedroom working and dropped off the defective at Easton Electric Motor Service in Port Huron Mi (Google will find them in one, URL in another thread by me)
Shannon, owner of Easton, found he could not get the replacement motor.. So he did one better.. I actually thing it's a better motor, He re-did the mount for me and when we were done it even lined up on the holes (GREAT JOB SHANNON) Just in case you ever need to know .. I think he saved the specs on the replacement.. it's quite a bit different. Works great though

Less than 250 beats a new Air Conditioner any day!
This won't help with your current problem though. No shut off is a control board issue.
Suggestion: Remove power (Turn off breaker) Remove inside panel, remove electronic panel from cover, clean well with a plastic bristle brush, YES, with no power (Pull fuse or disconnect wires) you can even use a damp cloth.. This may help. If damp clothing, dry well before reassembly.