Typically, if Dometic, the one in the living room controls the rear air conditioner, heat pump and furnace.
The bedroom thermostat controls the bedroom air conditioner. The forward one is an air conditioner only, no heat pump. Even though the thermostat says furnace etc. it only has air conditioning function.
Both thermostats are identical and interchangeable. Good thing for troubleshooting.
Make sure the fan is in "Auto" mode for proper functions.
Daryl and Marianne,
2019 3130re 20th Anniversary Edition
2016 F350 Lariat