Originally Posted by TG Twinkie
You will need a battery in the trailer and a functioning break away switch to be legal on the road.
To expound on this, the only thing the trailer battery does when towing is to power the break away switch. If you have an older break away switch it probably does not work anyway. Personally speaking, I would not let that stop me, but I would be extra special careful towing and check the break away switch when you can. The way to test the break away switch is to disconnect the 7 way from the TV and pull the pin. The brakes should activate. If you have an old switch you then may not be able to deactivate the brakes without disconnecting the 12v
to the switch. The switch should also be fused with a funky fuse in the 7 way access panel and maybe another fuse in the tongue.