It needn’t be a stormy night. In fact, it doesn’t even need to be that dark. The drama could unfold in that beautiful twilight just after the sun dips below the horizon as you speed back across the lake to the cottage. You snap out the switch on the dash for the running lights and cast an eye along the deck for the familiar red and green glow at the bow and the white stern light over your shoulder. Nothing. In, out, jiggle, jiggle. No lights. Funny, they were working last year.
It’s easy to forget about your boat’s navigation lights until the first time you need them — after dark. But don’t assume they’ll be ready to light up the night at the flick of a switch. When they don’t work, it’s because of a failed bulb, fuse, or battery or a broken connection somewhere between the battery and the light: at the battery terminal; at a junction or splice in the wire; where the wire meets a fuse or leaves it; at the switch; or at the light fitting itself.
Get in the habit of inspecting your boat’s running lights when you commission it each spring. If they don’t work, check that the bulb and fuse are good, then go over all the connections in case a wire has simply fallen off. If the lights still don’t work, try lightly sanding the contact points on the bulb and the bayonet fitting into which it plugs to remove any corrosion that could be interrupting the power. Also clean the contacts at the fuse, the battery, and the switch.
If all of that’s unsuccessful, you’re left with the possibility of a faulty switch, fuse, or battery. A simple 12-volt test light can cut down the time-consuming search; when it’s installed on the line it will tell you if you have power to the point of connection. You can also use it to determine if there’s power going into or out of a fuse or switch. Even more sophisticated – and a useful gadget at the cottage — is a multimeter, which provides voltage, resistance, and continuity readings for diagnosing problems with both 12- and 110-volt systems.