Does your T-stat do this?
We have a 2104S TT which has a Coleman-Mach thermostat. Have had trouble turning on the furnace the last two mornings. Slide the fan switch, on t-stat, to high or low and auto. Then slide the other switch to heat and nothing happens. After sliding the switch from off to heat a half dozen times the fan will start and we have heat. The T- stat works every time for the A/C. Sure seems like the thermostat issue to me.
The unit is under warranty. Just wondered if others were experiencing the same "shivering" effect.