Dometic AC unit fan out of balance?

We have a 2016 Grey Wolf travel trailer with a Dometic 13,500BTU AC roof unit. We used it last winter with no problems. It sat in our yard over the summer and we took it out last week for a short trip. When we turned the AC on for the first time it made a noise and vibrated as it the fan was out of balance. We turned it off immediately and just used a small electric fan for the remainder of the trip. We have dirt dauber bugs where we live and sort of thought they might have gotten in the AC and built a nest in the fan. Husband dropped the inside cover of the unit and has tried to look and see what the problem is. The squirrel cage does seem off balance as it always returns to the same spot when spun, like it is weighted there. He doesn't see anything as simple of a dirt dauber and isn't sure what it could be. He had hoped he could remove the unit from inside and sit it on the table and look at it. He has realized it needs to be removed from the roof up. This is not possible. He is too old and I don't want him crawling up on any roof at this stage of the game. We will call a repair place but since we are usually DIY kind of people I was wondering if anyone had had a similar problem and knew of a way to get to it from inside the the trailer and not from the roof. Since it gets HOT here in the summer we wondered if something from the roof or sealant could have melted ??? during the summer dripping on the fan. Just hoping for a way to fix it ourselves. RV techs are expensive on a fixed income.