Mike, the Perko is a double light. One bulb forward/steaming, one bulb aft. When both are on you have an anchor light. You probably just have burned out bulbs, or dirty connections.
Recommend marinebeam.com, I got these below (current controlled) for my running lights, very bright. I want to replace the festoon bulbs in the Perko at the top of the mast with LED's, but when I tried to remove the old bulbs, I couldn't get them loose, didn't want to break them since they still work.
- 1 x 30-LED 42mm Cone End Festoon - Mini-Max (FS-42-30C)
(Output Color: Warm White (bi-colored lenses))
- 1 x 30-LED 42mm Cone End Festoon - Mini-Max (FS-42-30C)
(Output Color: Cool White (anchor & stern lights))
Checkout Marinebeam website, they have a video demonstrating the importance of using current controlled LED's.