Random fan under bed with vent out of the blue 87' Rockwood

REALLY need some info here. We have a 1987 30'Rockwood RV, there are 2 round (heater looking) vents at the end of the bed very close to each other, that in this last year have never blown air, and not with the furnace on/off. They've always been dormant until a few hours ago, where some fan is kicking on for about 15sec and then quits, then repeats again in another 8-10 minutes. Keep in mind the furnace isn't on, hot water isn't on, and whatever fan that this is, it is not the furnace fan. As far as I can tell under the bed the vents run up to a black vent box with 2 hoses to the (hot water tank maybe?), I assumed it was some sort of heater/assist thing that would use the heat from the water (that's all a guess though).

My question is what the H is this thing, and what are some ideas why it would be cycling like that by itself out of the blue? It's really weird, and kinda annoying, going to be hard to sleep with it doing that, would it be ok to temp kill it? Think I could pull a term off it, but I'd really like to know what it is first.

Box is like 8" square black cube vented one side, it does say "Advanced Air AM Distributor inc" but I'm not finding anything on the internet. Has 2 vent hoses that come out end of bed 3" away from each other, they both seem to blow. The 2 black hoses feed into the top what look like copper fittings..the power inverter is maybe 6" near it, but nothing is bridged to it

Thank you in advance