You might try to research your trailer to see if some kind of a remote was part of the OEM package. I have a remote with my trailer that operates the slides, awning, front and rear stabilizers, and a scare light on the door side. It took me a while to discover the "scare light icon" on the remote, and to figure out that it overrode the inside switch. At some point I had apparently turned the light on with the remote, and couldn't figure out how to turn it off until the dealer pointed out the remote also controlled that light.
Good luck.