was the battery replace recently, when you say "a new battery"?
if so, many times the battery wires get crossed and set off a resettable breaker/fuse that's inline, between the battery and the front of the trailer.
it's usually located along the A-frame of the tongue.
simply by pressing the black button, will reset the breaker/fuse, IF you have the battery wires correct.
Dan-Retired California Firefighter/EMT
and Zoe the Wonder Dog(R.I.P.)
2016 PrimeTime TracerAIR 255, pushing a 2014 Ford F150 SCREW XTR 4x4 3.5 Ecoboost w/Max Tow Package