I have a 13 Ram, heater has never worked all that well. 2nd owner since 2017. Had the water pump recall yr. ago. Which coolant goes in? Purple or orange.(??)
If your truck is a Tradesman you are simply doomed. Every Tradesman and Express I've ever been in have been marginal at best in true cold weather.
My little VW on the other hand will literally melt your eye balls out on a 0 degree day. And it's got 17 years on the OEM heater core.