Pulling a small load, 16ft trailer with 4 Round Hay bails. This past weekend, and I got hot, not the truck. Trans and Engine heat same as always, but the heater was running me out of the cab. Outside temp was low 30's, turned the heater to cold, vent, even tried to turn on the A/C. Heat coming out of the vents was so hot you could barely stand to have you hand in front of it. Any thoughts. I pulled over gave everything a quick look over, no thrown codes, no fluids, no odors, so I headed back down the road. After about 1 hour, 50 miles later, everything started working again.