Electrical mystery

[Hunt Herrigel]

I have a Catalina 30 that has three 12v lights on the starboard side. I also have a navigation light over the nav table. On Friday evening all lights were working fine. An hour later I tried to turn on the 3 lights and none went on. The nav table light works but if it is on and I try to turn on one of the three lights, the nav table light goes off. Anyone had anything similar or any ideas what it could be?Thanks

 

[John Finch]

Loose ground (common) connection

Hunt:it sounds like you have a loose connection on the common buss. This is acting like a giant resistor, and is not letting enough current flow to supply the lamps. You need to have an electrician or technician find and repair it, as it could cause a fire. A fault like this will not blow a fuse of trip a circuit breaker, but will heat the loose connection to a hazardous level.Good luck,John Finch, s/v Doxology

 

[John Finch]

Look on Cabin Lights switch

Hunt:P.s.: A good place to look is the quick-connect (push-on) terminal (probably a black wire) where it connects to the back of the "Cabin lights" switch on the main electrical panel.Be sure to unplug the shore power before opening the panel.Good luck,John

 

[John Mavrovich]

Mystery

Try disconnecting all three light fixtures. Then reconnect - but after connecting each one, check that it works (along with the nav station light). One of these (when connected) will probably create the failure you've described. I suspect that by process of elimination, you will determine that one of these is faulty - something loose or corroded perhaps. It's certainly a curious problem. Good luck.