Hi. New to the forum. I’m a first-time travel trailer owner and have experienced way too many issues in the first 4 months of owning my 2023 Keystone Outback Ultra-lite. Most recently, I have experienced a loud rumbling and vibration of the trailer in the middle of the night, that wakes me up 3-4 times a night. It only seems to happen when temperatures are close to, or below, freezing. I have more testing to do, but it also seems like it is only when my tank heaters are turned on (could be coincidence). I’m almost positive that it is the furnace. Possibly the blower fan? I believe this happens randomly and not always when the furnace kicks on for heat. Would anyone happen to have advice on what I should look for to narrow down where the problem lies? I’m stationary and it’s a big hassle (and expensive) for me to get a mobile service tech to check it out, so I’d like to trouble shoot a bit before doing that. Any help would be appreciated.