Sounds like a wire might have come loose for the light. There are 3 wires coming out of the side camera / light. One is ground, one is power to the camera, the other is power to the light. It's possible the wire connection going to the light came apart, or the wire broke at the connection.
If your's is anything like mine, the front side marker lights can easily be accessed from inside the propane tank bay area on each side of the camper. Open the propane tank door and peal back the covering on the wires going to the camera/light. See if one came looses.
This would be my starting place before settling on purchasing a new unit.
FYI, on my camper, I installed the side camera / lights about 2 years after we purchased the trailer. I had problems simply removing the old amber running light, especially when the pass through door blocked the view. First, the holes did not match, second the view was obstructed by the pass through basement doors.
I solved the issue by leaving the original lights in place, simply spliced into the existing wires going to the original light and installed the camera/light higher up, directly above the existing so the view completely cleared the basement door. It worked. All the wiring was done inside the propane tank compartments.
3 wires, I bet one of yours came loose.
