Loss of Power when Furnace Blower Shuts Down??? Help!!!

We just cut power to the whole camper and checked batteries and they showed 1/3 and that quickly went away, too. So...changing those today.

It's a 2018 Keystone Cougar 30RLI. We have tried turning off the batter ugh disconnect and turning it back on. Does the same thing both ways. The fireplace worked when the power shut off this morning...that was how we heated last night. We have that battery disconnect, but we still dont know how it actually works. I only mention that the lights randomly come on when power comes back on because I thought there might be an indicator for someone. We have thought it might be the batteries, but they show full with that battery disconnect turned on so we still may just need to unplug the whole camper? My husband doesn't want to plug it in without the surge protector for fear it might fry something, but...there is no indicator showing that it cut power... there's a ton of lights on it... everything appears to be normal.

It's hard to understand any connection between the 12v furnace blower and your 120v microwave & TV. You haven't offered much detail about your RV so far that would help much. Do you have an inverter?

I'd remove the surge suppressor to see if anything works differently without it.

What have you tried so far to troubleshoot on your own?

What is the battery voltage? Try unplugging and then measure battery voltage again after a few minutes.

Is the surge protector a full EMS that will cut power? Does it give a prior error code to indicate power was cut?

It could very well be batteries going bad.

furnace has absolutely nothing to so with the 120 volt system. Lighting is 12 volts. Are your touch lights 12 volts?

The furnace blower is 12vdc. The tv, micro, and other outlets are 120vac. Need to be diagnosing the 12vdc system from the batteries all the way up to and including the converter or inverter/charger, whichever you have. Not sure of a quick fix to get through the night, sorry.