Navigation Lights Shorting

[Carmelo]

This should be an easy question for those that understand and are familiar with testing electrics.

Both my masthead tricolour and anchor lights have stopped working. I am not sure if it happened at the same time. When I turn either on (they are switched using the circuit breaker at the panel and are adjacent breakers to each other) both the indicator lights on the panel glow (ie even the one for which ever circuit is still open glows although the switch is off).

Before I head up the mast to look at the fitting, does the behaviour of the lights on the panel give any clue as to where the problem might be?

Thanks

[captain465]

Check your ground connections.

[Dick Pluta]

Second the ground suggestion.

Dick Pluta
AEGEA

[Carmelo]

Sorry to be stupid, but by "check the ground connection" do you mean where the negative (black) wire returns to the panel, generally along the the length of the negative wire or something else?

If both lights go on when only one circuit is on then that means there must be a short between the circuits? Could this through the ground connection?

Many thanks

[DeepFrz]

May you could pick up the "12 Volt Bible". It might help you understand what you need to do.

[GordMay]

Originally Posted by Carmelo

... If both lights go on when only one circuit is on then that means there must be a short between the circuits? Could this through the ground connection?
Many thanks

No. It would be on the Positive leg.

[fairbank56]

Is there a connection at the mast step? Junction box maybe? Check there first.

Eric

[Unicorn Dreams]

Beat me to it Eric

[senormechanico]

Sorry Gord,
The OP said the lights stopped working.
If there was a short, BOTH lights would burn brightly.

It's the navigation light's ground connection that's bad (open).
+ goes to one indicator filament, then to one navigation filament, goes PAST the ground, through the other filament and returns to ground via the OTHER indicator lamp. Various filaments would burn in different states of dim to nothing depending on their current rating. The indicator filaments would burn the brightest.

[GordMay]

Originally Posted by senormechanico

Sorry Gord ...

...It's the navigation light's ground connection that's bad (open).
+ goes to one indicator filament, then to one navigation filament, goes PAST the ground, through the other filament and returns to ground via the OTHER indicator lamp ...

Never be sorry for being right.
Thanks for your cogent analysis.
My apologies for my erroneous observation (two mistakes, just this week)):