Trailer Question

[Beaches]

Tires keep locking up. When unhooking trailer awhile back, forgot to unhook the emergency brake lock chain. I pulled truck away activating the brakes. I reset the chain, however my tires are still locking up. Any ideas? Do I need to bleed the brakes? Not sure, what I am missing?

 

[POGE]

Just some ideas I am no expert at all on this. Actuator on brakes if equiped? see if stuck or does not slide freely.
Might be wiring plug in pin connection ? Try backing up trailer then forward with some one driving so you can see if actuator or other parts not working correctly.