Originally Posted by wmtire
Are you currently connected to any form of 120 volt AC shore power?
Does any other 12 volt items work (lights, pumps, fans)?
There is usually a resettable "fuse" on your frame rail, just back from your battery that may have tripped.
There are some pics of it in this link, and there is a small button you push in on to reset it.
I would look now at the ground connection from the battery to the frame of the couch. Depending upon the house wiring, if the ground is inadequate nothing 12 volt will work. Even with the converter running off the 1:20