Originally Posted by cw3jason
Check for fuses on the back side of the converter. There should be reverse polarity fuses and if someone accidentally connected the battery wrong it will blow those and you will not get power. should be 2 or 4 fuses. That should only effect your DC side of things, which is just about everything accept air conditioner, microwave, and 120v outlets. if those are not working and you are plugged in check your main circuit breaker and make sure you have ac power coming into the trailer.
Just to add to what Jason stated--
Make sure what you plug into is energized and is putting out power.
If you are using an adapter that goes from 30 amp down to 20 amp, make sure that is OK. They have been known to cause problems.
When you are plugged into ac and if you have a meter, check and see that you actually do have ac coming into the panel on the trailer. If you are sure there is power where you plugged into but no power at the panel, then you should take a look at the cord.