the trailer may have had a very slight drag to it if any. By no means where they locking up . Started out for home everything seemed fine no drag noticed. About half way home got a small whiff of brake, then 5 minutes later “service trailer brakes” message appeared on my dashboard in the truck, tried activating. Brake controller manually and noticed no power. By then I was on freeway , so eased off acceleration and slowly got down to a limp speed.