We had a cable problem with our trailer from day one.
The dealer was not able to diagnose it very well because they did not have cable tv there.
What I did was to gut all the cable (with the exception of the run back to the bedroom tv) and re cable everything.
The bedroom cable got new connectors.
The culprit turned out to be the cable splitter located in the wall behind the living room tv.
It was a cheap piece of cra......um...I mean...ah....junk
On a side note, evey one of the connectors were loose. Must have been a new guy working on my trailer that day.
Everything is fine now.
You can get a spool of cable from home depot and all the tools you need too.
I had them left over from last year when I ran cable throughout our house.
It's not to hard to do.
Hope this is helpful.