Way to go! Walt & I just got our boat trailer lights working again - burnt bulb (1157). In doing some online searches, there is indication that before launching (with these type of lights), you should let the bulbs acclimate to the temp before submerging them. And always disconnect the lights when backing down. Not so much an issue with LED's, but quite a bit less costly for us cheap fishermen.
Prior to our attempt at diagnosing the issue, I did some online video searches. Lots of confusing dialog out there. Trailer lights are definitely no fun!