Your trailer plug's wiring goes to a junction area at the end of the main wiring harness . It could be in a box, a terminal strip or just several connectors grouped together. Using a wiring print, wire colour or a multi meter, isolate the hot wire from your truck. If you disconnect this wire from your truck and connect the trailer wire to a source from your battery B+, you will now be utilizing only the trailer's battery.

Be sure to terminate the end of the truck wire to eliminate the possibility of shorting the wire and blowing the truck's fuse. You should also install a circuit breaker or fuse in series to protect this new circuit. I did the same thing on one of my trailers. Using a single pole, double throw switch, I enhanced the circuit, by being able to provide both power sources, either the truck or trailer with a selection of the switch.

Gard

I would be surprised that you do not already have a converter if you are able to run 110v and 12v.

You should look a little closer to the circuit trail.  110 has to be converted to 12v to run those interior lights that generally run off the truck.

it is a nice winter project to add an inexpensive converter.  Allowing the shore power to charge the battery you install at the same time.  And as you are driving the converter will also charge the battery.

Check out PD web page for some factory info.

http://www.progressivedyn.com/index2.html

Additionally, was your interior installed professionally?  If so call the company that installed it.  Most likely all those lights you mention were installed to run off the 12v system and there may be a blown fuse.  this can be common.

Was your LQ installed professionally?  Did you buy it new or used?  If it was installed professionally I stick to my first statement that a fuse may be blown. 

You did say originally that your weekend package operates on 110v??

The whole idea of having an independent battery system, is to be able to turn on the lights, when ever the trailer is not connected by a shore cord or to the tow vehicle. The converter is not used in this lighting circuit, other than to recharge and supplement the battery.

Gard

  I think the confusion is in knowing which lights are being powered by what source. In both of my LQs, I have 12 v lights that are powered by two different sources.

With my Showtime interior, my stalls, mid tack and tack lights are powered from the tow vehicle, unless I have the shore cord powered. My interior lights will run off the batteries if I turn on the battery master switch, or run the shore cord. I have modified my stall/tack  lights, as I previously mentioned, to now run directly off the battery or tow vehicle.

With my Sierra interior, I can turn on any switch and the lights will run off of battery power. With the shore cord connected, the converter powers and supplements the battery.

Each conversion company has its own way of running the power for the lighting, so it is difficult to directly compare one trailer to another, unless they have a common builder.

Gard