on my 1985 hilo it has 110 electrical outlets inside but they only work if you have the trailer plugged into an outside 110 source...the trailer has an inverter that should convert the 12 volt battery to 110 ac...is there a switch somewhere i have to use to run the 110 outlets when not plugged into an outside source?

If your trailer is like all other Hi-Lo trailers you have a 'converter', not an 'inverter'. The converter only converts 110 volts to twelve volts for the trailer's inside circuits, not 110 volts, and charging for the battery when plugged into shore power. You only have 110 volts from the outlets when plugged into shore power. This is typical of most travel trailers. To get 110 volts when running on the 12 volt battery you would need an inverter. Those can be installed in the trailer but can drain the battery quite quickly.

__________________
My Great Wife Joyce
2018 Jayco Jay Flight 21QB
Formerly owned 1705T and 2310H
2012 F150 4X4 SuperCrew EcoBoost w/Leer Cap
Reese WD Strait-Line Hitch
Amateur Radio K3EXU

so basically its a battery charger?

Yes, plus it is what would be called a "battery eliminator" in that it converts 110 AC to 12 volt DC so you can operate the lights, furnace, radio, water pump, the fridge in 12 volt mode, and the water heater ignition if it doesn't have a pilot light. You could operate all those those without the battery. But, you do need the battery to lift the top because it takes more power than the converter can muster up on its own.

__________________
My Great Wife Joyce
2018 Jayco Jay Flight 21QB
Formerly owned 1705T and 2310H
2012 F150 4X4 SuperCrew EcoBoost w/Leer Cap
Reese WD Strait-Line Hitch
Amateur Radio K3EXU

thanks for the info rich

Beware of the inverter. It will run down the batteries quick.
Seems most campers are made to be plugged in, so boondocking requires some modifications. The more you can convert everything to DC the longer the battery will last (opposed to using an inverter).