[jjwhite368]

Check your 12 volt fuse panel. Find your furnace circuit and look for what is in the slot. If it is black (like the one in the picture) it is a self-resetting circuit breaker. Our dealer maintenance manager had us replace it with a standard 20 amp automotive fuse (yellow).

Our symptoms in our brand new 2021 3121RL were exactly the same. On, run for a little while, cut off. Wait a while, come on, run for a while, cut off. The dealership guy said he had seen this in a number of Keystone units (not just Montanas).

It was the fix, toasty warm after. We discovered the issue on our first night, a Sunday, and we slept with the best temperature all night at 58.