Trojan Boat Forum

The side lights on my F26 have 12V when measured with a multimeter but the light bulbs do not light. The previous owner mounted a combination bowlight that works so I'm legal for night running. I'm just wondering why/how the sockets would have 12V but the light bulbs stay dark. The bulbs work in other installations, so I know the bulbs are good. Any ideas?

are you checking 12V + and the ground across the fixture ? is it a bayonet or socket bulb ?
If a socket style, do you have the correct bulb, some have two contacts on the bottom, some have a single contact, the locking pins will fit but the bulb wont light with the wrong pin / socket combination

just some ideas you may already know

The bulbs are festoon bulbs with the electrical contact at each end. I'm measuring the voltage between the two electrical contacts that the ends of the bulb sit in.

Voltage is different from current, and the light needs both. You can measure 12v and have insufficient current to power the bulb. Most likely you have a corroded contact somewhere (not necessarily at the bulb) which is preventing adequate current from passing. Try loosening and re-tightening any screwed-together contacts that feed the light (both positive and ground). If that doesn't work, turn your attention to crimped connectors. Good luck.

As I went to hit "preview", it occurred to me that the bulb contacts may be riveted. Check them for corrosion that may be preventing good electrical contact.

Also try light sanding of contacts and bulbs which I have to do from time to time.