Your T'stat may have lost it programming. I have seen this happen with the Dometic Duo Therm units using the Comfort Control Center T'stat. If this is your set upTry doing a reset on the T'stat. If four button while the T'stat is off hold down the mode and down button and turn it on. On the five button it is mode and zone buttons.
Mike, RVIA & RVSA Certified Master RV Technician
Amy, Dr. Assistant - Roxie & Mei Ling, four legs each
2000 Gulf Stream Scenic Cruiser 450 hp & 1330# torque
06 Saturn Vue, 06 Chevy Z71 4x4 & 2014 Corvette Z51 M7