Will gauge lighting work off SPDT switch?

Saabu

Cadet
Joined
Oct 23, 2011
Messages
6
Good Day,
working on an old Vanguard from 1981 with a Johnson 140hp. very simple boat, all wiring is exposed and accessible.
my tach, Speedo, Tilt and Fuel gauge all have bulbs but are not wired for power.
My Nav lights are a simple old SPDT push pull switch with Head, Batt and an unmarked terminal (last one i'm pretty sure goes to switched power in the distribution box under the dash).
i've searched the web and havent found any video or post dealing with running illumination off that SPDT switch, at the first pull (anchor light).
i'm assuming i could jump say a blue wire from that terminal to the gauge lights.
Thanks in advance for any suggestions,
Wayne
Kenora Ontario
 

Saabu

Cadet
Joined
Oct 23, 2011
Messages
6
I’ve found a push pull On Off switch in my stores so think I’ll install that to control the gauge lights…
 

alldodge

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Mar 8, 2009
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42,054
Wire gauges lights to Nav light position (when all lights and anchor is on
Wire anchor to other position so gauges are off when just anchor is on
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,840
Common Navigation lights are wired so you can turn on just the anchor (or stern light) when at anchor at night, or when underway, turn on the bow and stern lights. I am not sure how to wire a SPDT switch to do that without a diode. A DPDT switch would work.
 

dubs283

Vice Admiral
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Jul 27, 2005
Messages
5,322
Oof, memories of sea ray nav/anchor light switch. You know the ones with a transom light and forward facing mast light?

A diode is necessary at the switch to not back feed current to entire circuit when only the anchor lite(s) is illuminated
 

Saabu

Cadet
Joined
Oct 23, 2011
Messages
6
Oof, memories of sea ray nav/anchor light switch. You know the ones with a transom light and forward facing mast light?

A diode is necessary at the switch to not back feed current to entire circuit when only the anchor lite(s) is illuminated
just to clarify, i'm going to use a separate push pull On Off (SPST) switch powered by the disabled wiper motor to power the gauge lights. i'll leave the SPDT Nav light switch alone. i'd read that its prolly best to keep separate circuits if possible to simplify troubleshooting, etc.
 

04fxdwgi25

Chief Petty Officer
Joined
Mar 25, 2022
Messages
537
Yes, gauge lighting will work off any kind of switch, unless there is some exotic lighting system / control . Sperate circuits are best.

PS: lots of boat manufacturers don't use a switch for gauge lighting. They just run it off ignition switch.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,840
You can wire the gauge lights to the navigation lights, as well. Why use another switch for the same function?
 
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