Change out thermostat

Dometic makes a digital that works well. Probably pricier than a big box thermostat but does not need a battery backup and the wiring is identical. The last two trailers got switched to the digital as soon as we got them as the analog one have way too much swing. Maybe 2 or three degrees swing and life stays comfy.

Thanks for the info. Just ordered one from Amazon. Should have done this to start with..

Maybe the differential isn't set right on your existing T-stat. You have to know how much the control circuit draws.

It sounds like you have the wrong accumulator setting for your current thermostat. Check the user's guide or just make an adjustment to see if that fixes the issue.

At a minimum you can keep it for a backup when/if the new digital thermostat dies.