No voltage at cabin light - how trace wiring?

[RichW9603]

Hi all,
Apologies if there is a thread on this, I searched and could not find it. I recently bought a 1989 Hunter 33.5 and am fixing a few things. The light above the sink (port side) and the light above the nav station (also port side) are not working. The light above the port seating bench does work, so it's not that the entire port cabin light switch is bad. I removed both of the unworking lights and, with the port cabin light power switch turned on, tested for voltage. There was none, no 12V was getting to the lights at all. The problem is, all I can see is the two wires going into the ceiling and then heading off to heaven knows where. I am guessing the problem is, for both of these lights, and one or both of the wires is cut somewhere along the line, but I don't know. Maybe they both became detached at the power panel at the nav station, I have no idea.

Has anyone run into a situation like this before where they had to trace down the reason voltage was not getting to the output wires?

Thanks for any thoughts.
'Dubs

 

[kloudie1]

I am not familiar with your boat, but Hunter wired the cabin lights all on the same power wire, starting at the panel.. going away from the panel, open the last one that works and look at its power wire. There usually is a spade with a couple of wires .. one is power to the lamp and the other takes power to the next one in the chain.. The connector for the power to the rest of the lights might be a problem. You may have to look a little "upstream" of the light to find that connector, but it is usually only a couple of inches inside the liner at most from the fixture.
They did the grounds that way too but if you have no 12V at the other fixtures, the ground side may not be the problem. If you are metering between the terminals of the fixture, an open ground side would give a "no power" indication. so it could be the series connector on the ground side too.. If you run your negative meter lead to the ground side of the working fixture, uou'll get a true read on the power wire to the other fixtures..

 

[Terry Cox]

As already mentioned, pull the light fixture wires out of your headliner and make sure that both feed wire crimp splices are connected to the fixture wires, and confirm that you have voltage on the feed side of those crimp splices. One of ours came undone. If not okay there, you may have to use the old feed wire from the non-working fixture as a fish wire to pull in a new feed back to the next connect point, wherever that is. I'm assuming that you have already checked the feed wires at the electrical panel circuit breaker for voltage.

Again, I'm not familiar with your boat model, however Hunter seemed pretty consistent in the way they wired their boats. Many of our lamps are looped in series using one feed source from the panel. It may be a matter of determining all the lamps involved on that circuit, then fishing in new feed wires to each, before you find out the defective source.

 

[Ken Cross]

Make sure your measurements are good. By that I mean the ground your meter was connected to could also be bad. Run a wire to the negative battery terminal (or any other known good ground) to the negative meter or test light lead. I've seen many people who fail to acknowledge the ground is just another conductor and subject to the same failures.

Corrosion is the most common electrical failure on most boats. That can be anything up to completely separated conductors or sometimes it looks great, but won't conduct current. Sometimes a test light is a better instrument to do this kind of work than a multimeter because it requires more current which helps locate corroded connections.

Ken

 

[RichW9603]

Hi everyone thanks for the great ideas. I did not see any wires leading off to the next sequence in the daisy chain do I will get a little mirror and try to look in the headliner space. Question, if I can't find the original wires and need to run new ones, any idea how to do that? I may need a long semi-rigid rod to stick in, any ideas on what I could use for that?
Thanks.
'Dubs

 

[GorillaToast]

Hi everyone thanks for the great ideas. I did not see any wires leading off to the next sequence in the daisy chain do I will get a little mirror and try to look in the headliner space. Question, if I can't find the original wires and need to run new ones, any idea how to do that? I may need a long semi-rigid rod to stick in, any ideas on what I could use for that?
Thanks.
'Dubs

For less than $20 at your local HD, you can buy an electrician's fish tape which is designed specifically to do this kind of task. Google "fish tape" to see what I'm talking about.