firstly, welcome to the Z, don't forget to stop by the newbie section to get the official welcome.
As for the cruise, a couple of stupid questions first (not being condescending, just have to ask them) were you doing more than 35MPH? you did press the ON button down fully? I know my old Dakota had a shady buttom.
If both were answered yes, my bet would be a faulty switch as the most likely and cheapest to fix. If that doens't work, then you'd be looking at a programming/electrical issue, and that's where my experience can't help ya.
I'd try the switch first, you should be able to pick it up from the dealership, and I hope to god it's not a whole steering wheel assembly they tell you you need. Should just be a part with all the controls. If you need a diagram or something, try getting a hold of RamTECH, he should be able to get you what you need.
started my truck this morning and had no problem pushing my cruise control once and the light lit up on the dash, so idk if it was just that the electronic part of it might have froze, i mean i do live in ND right now and it's been getting below 0 degrees every night