Driver side turn/brake signal
Had a wonderful weekend at Harper's Ferry KOA with the fam in our 21DK. After breaking down camp to return home, the driver side blinker and brake signal would not work. I removed the exterior cover and one of the two filaments on the bulb was working. I replaced it and saw the same issue. The running filament was fine, but the brake and turn filament was producing no light.
Does anyone have a recommendation on the next steps to diagnose? I am going to recheck the vehicle and camper fuzes but after that have no idea how to troubleshoot. Thanks in advance.