Generator and Transfer switch. I found the issue, the generator has two circuit 30 amp circuit breakers. Opened up the cover one was tripped turned it on and now everything works.
I recently installed a second air conditioner a Dometic Penguin 13,500, on my 2009 3051RL the trailer had a Dometic 15,000 already installed. I have been able to use both air conditioners with my Onan 5500 generator until the last camping trip. When using the generator the 13,500 does not start and about half of the electrical recitals have no power. When I plug the trailer into power everything works including air-conditioners and all recitals. I'm thinking the transfer switch has gone bad any help would be appreciated.