Dometic AC vibrating/shaking

Thanks all. When I had light this morning I was able to find a dirt dobber nest on the outside of the fan that was causing my issue. Just couldn’t see it last night. A little difficult to get to it but we are back in business.

Does it shake on FAN mode?

Most A/C's have a Fan/Blower motor. on one end (Outside where you can see it when you remove the outer cover) is a fan. I've had insects build a nest (mud daubers) on this fan.. I've also had a fan "Blow up" on me (Hey it was made in China. you know. China bombs) You may need to remove a 2nd "inner" cover to see both sides of the fan blades or to service it.

Then on the other end of the shaft, under a cover, is a blower cage. I've seen these crack and fail as well.. not on my Rig but on a neighbor's.. He got lucky (it was late Friday. Hot as Double hockey sticks, and no way could he get to a parts store before closing.. I had a spare I did not need. so he got lucky).

I"m guessing your problem is either the fan or blower.

Hold down bolts should be finger tight then SNUGGED up....40 INCH pounds torque (INCH not FOOT)

Also if fan mounting screws are stripped they will appear in place but not really holding motors in place when it runs
Broken fan cage/blades
Critters

The AC unit is mounted from the ceiling of your coach! Pull off the INSIDE cover, and you'll see four bolts that need to be snugged down. While you have the inside cover off, clean the filters....Dennis