Lighting Wiring: Multiple ON switches, Need reverse current circuit protection? (1 Viewer)

[FishNinJay]

I'm thinking of installing some small rear LED spotlights, probably under my bumper.
And.. maybe some on the sides or corners of my roof rack. Who knows?
I already have a front LED bar on my ARB bumper.

If I'd like one of the rear LED spotlights to also light up when I'm in reverse, I was
wondering if I just splice and run a pos wire from my current back-up light wiring?

But, I'd like a separate switch on my dash to turn on all the rear LEDs, or possibly
ALL my LED lights (front bar, side, rear), like for zombie patrol, or camping lights?

If I do that, and have multiple switched/fused positive leads to the LEDs spotlights
in various configurations, do I need any type of circuit protection for reverse current?

I did a search here and got nada.. on Google, I got a few hits, that mentioned
putting a DIODE in series, and in particular, a mention of a SHOTTKY DIODE, because
there will be less forward voltage drop. They sell these on Amazon, but I'm not quite
sure how to wire these? My understanding, is that diodes only allow unidirectional
current? so it seems like I could have multiple ON wires going to the same LED, and
if they all have a diode inline, then there shouldn't be any stray current going
elsewhere causing electrical gremlins. Yes?

Any help? Or a wiring diagram? Much appreciated...
- Jay

 

[jawjatek]

Yes. The diodes have a line on the body for the cathode. The cathode side goes on the side of the lights; all the cathodes connect together and "feed" the light. The other side (anode) of each diode goes to each switch. This is called "wired-OR"; light will come on if "one OR more" of the switches is on.

 

[Output Shaft]

You could splice into the reverse light circuit for additional lighting IF the added lights don't draw too much power. A better alternative for brighter backup lights is to just swap in some CREE 7W LED (Q5) bulbs in the backup light sockets (socket size 1156). They're super bright and will give you all the light you need. Not only are they super bright, but each bulb only draws 7 watts... vs the whopping 27 watts the stock incandescent slurps down ( per bulb).

But here's a wiring example using 3 regular old incandescent light bulbs ( you could have more).
Each bulb is in a socket that has two wires coming out of it. One of the wires goes straight to ground, and the other goes through a switch to positive (or vice versa).
Each bulb is wired this way. Super simple. Each one is on its own circuit. 3 switches are needed to turn on the 3 lights individually.

Now if you wanted one master switch to turn them all on at the same time, you'd need a 4th switch as the master. All of the + wires coming from the bulbs would require a splice before the individual bulb switch leading to the master switch.

But (IMO) a master switch seems overly redundant. It's easy peasy to just flip on 3 switches. Then there's no confusion ( and one less switch to wire).

I see no reason to use a diode. But maybe I'm missing something.

 

[FishNinJay]

Thank you. Yes, it was also my plan to eventually swap out running lights and reverse bulbs for LEDs. My understanding was the turn signal bulbs needed to stay incandescent to work with the blinker relays?

Yeah, I'm thinking the "Master Switch" all-on idea might not be as good as the simpler idea of just flipping multiple switches on.

I might still try to splice 1 small supplemental LED into my backup light circuit. If I just splice it, with no diode or reverse current protection, what's the worst that could happen?

Again, thank you!