Trailer light wigging out

The passenger side is working correctly. Remove the light from the pass side and replace the driver side. If it works go buy another light.

 

And if it doesn't work, check the plugs, terminals, & power wire.

There should be a ground, power, and a blinker wire.

 

Alot of small trailers are just wired that way. The manufacturer just ties that side turn signal into the same circuit as the brake, turn, tail light. My LoadMax was the same way. Hit the brakes, & the side blinkers light up solid amber in sync with the brake lights.. LoL

If they are not led, the dim filament (marker) is probably just burned out. If they are led, you may just have a defective light, wiring, or bad connection..

Do what @Slay said & swap lights with known working one to see if it's just the light fixture itself..

 

X2 the amber lights on the side shine solid when I apply the brakes