Have you considered buying a Ram Classic like your old truck? They still make the old version you have and sell them brand new, and they still have great AC units, and all the bugs are worked out of them of course...DO NOT settle for that faulty New Ram AC,
if the dealer will refund your money and give you your old truck back or perhaps you buy a new 2019 RAM classic and get the difference refunded might be the way to go. Although you shouldn't have an issue with the 2019 Ram classic I would still test the AC with a thermometer just in case Chrysler is using different parts now that could affect the Ram Classic 2019 as well as the brand new Ram truck models. Good luck and please follow up for us with your outcome! Thanks friend.