If it is new, and it were mine, I would measure the voltage getting to the brakes. This will have to be done at each wheel. One person under the trailer with a voltmeter, and the other in the truck cab, not using the foot pedal, but holding the manual override until the reading says 10, or whatever the max is. That should give you close to 12 volts on the brakes, which is enough to lock the wheels. If there is no voltage, then trace that problem. Otherwise look at adjustment.
Now with that said, some trucks came with a towing package, but relays and fuses to make it work were in the glove box, and not installed in the truck. May want to check your truck owner's manual bout the brake fuses and battery charge relay for the towing package, if you have these, and have them installed.
2012 Ford F250 ext. Cab 4x4
2002 Jeep Wrangler Sahara
2008 Yamaha V-Star 650 Classic
2008 Work and Play 18LT