2004 Mainship 400. My interior cabin light above the lower helm does not work. I don't use it but I know it worked when I bought the boat 4 years ago. This light has 2 switches. One on each end of the fixture. It has two FL tubes in it. One is regular white while the other has a red filter on it for night vision. I also have a rocker switch on the lower right side of the helm that I think controls the light, or at least part of it. I took the light down and have a blue and a yellow wire coming into the fixture from above. When I tried to test it for power I got funny readings on my meter. Nothing like 12v. I was going to take the fixture apart to see if there is a ballast that can be replaced. I would need to drill out a couple pop rivets to take it apart. Before I did that i wanted to check here for wisdom and guidance. I suspect there is not replacement fixture available that would fit the opening or match the other lights. I should have taken pictures and certainly can do so if that helps.