Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
It seems like everytime I have to use one of my mast lights (which is not to often) I have to clean the connectors where their cables exit the deck. I have this trouble with both the anchor and spreader lights. You may have the same problem and a blown stern light. The stern light is easy to check. You will want to check all of your connections before you climb or lower the mast to check the others. If you don't have a VOM (voltage-ohm meter), you need one.
Are these lights on the same circuit? My steaming light is on a different bus than my running lights. If they are the ground is suspect being common. If not, stern light is easiest to check, so clean contacts, test for flow with meter. If no flow check flow with each terminal connected through meter to ground wire from battery. If no success yet your ground from stern light must be fautly.
The most likely cause for all of your white lights to fail at the same time is either corroded or loose connections. You can use a multi-meter to check continuity in the circuits. And/or check the connections and buss bars for loose or corroded areas.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.