Hey man, my jeep is in shop for same heater as you. Thanks for posting your warranty write up, I took them in to show my dealer. They said I got mud in mine. (bunch of BS) did you get a look at your coolant or inside the overflow bottle? mine looked brown (hence why they said mud, and there was something that looked oily at the bottom)
They are trying to charge me labor on this, but warranty the parts.