Re: How to test stern lights
Lets try a little logic here. If a table lamp in your house doesn't turn on when you hit the switch what would be your first inclination?
I think 99% of the population would try replacing the bulb just after glancing at the power cord to make sure it is plugged in don't you think? If that doesn't work you DO NOT start replacing things -- you begin troubleshooting. For 12 volt circuits all you need is a test light (about $5.00 or less) for basic testing purposes. If the bulb has been replaced and when you did that, you also looked at the socket to see if something wasn't wrong in there, then turn on the switch. Connect the ground lead for the test light to ground. Since you have limited electrical knowledge, that would be the negative terminal of the battery or the ground buss connected to it. Using the probe, touch it to the input (the LINE side) of the switch. This line comes from the fuse panel and provides 12 volts. If the test light doesn't light, move backward to the fuse panel and check for power on that fuse. If you have power at the panel and not at the switch - you can draw the conclusion that the wire is broken or disconnected at either or both ends. No power at the circuit side of the fuse says -- hey -- check the fuse. If you have power INTO the switch, check the output (LOAD) side of the switch. If you have no power there the switch is bad. If you have power there, check at the center terminal on the light socket. If no power there you can reasonably assume the wire between the switch and the light is broken or disconnected at either or both ends. If you have power at the socket there is a bad ground wire connection. So the short answer to your question is Yes -- it may be the bulb, the wire, the switch or lack of 12 volts to the circuit. But as others have suggested, you really need to get some Low Voltage 101 education if you intend to install or troubleshoot boat electrics.
