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Emergency lights wiring

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New Member

I have a question that has left me a bit confused, and i hope you guys can help me out:

I am going to install a strobe lightbar and and body-mounts on my responder vehicle, and its preferred to be as simple as possible: one rocker switch turns all the lights on and off, and i use one of the flash-patterns on the bar.

The lightbar i'm going to order comes with a wire-harness containing 15 wires, several of them for functions i do not need. I am interested in the function from the purple wire that makes the entire lightbar light up.

Do i then "plug" the other wires, and join the purple wire with the red power-wire to the switch? And of course ground to ground through the switch

Best regards,


Well-Known Member
Most Helpful Member
There's no real way we can answer your question.

One possible way things to work, would be power and ground and the wires where one of them goes to ground to select the pattern.
Power may or may not have to be switched depending on quiescent current.
If this were the case, a DPDT center off switch might be able to be used. One pole would switch power and the other would select one of the two modes you use.


New Member
Ok - thanks - today i spoke to some people and as i understand i can join the power-wire together with the relevant flash mode wire to the switch.
But the bars ground itself - should i run that directly to the battery without going through the switch?


Well-Known Member
Most Helpful Member
Here's http://www.extremetacticaldynamics....l-guides/912-full-size-led-light-bar-install/ an EXAMPLE of "stupid instructions".

To power the full-size LED light bar, you will need to locate the unit’s red and black wires. The red wire needs to be connected to the unit’s switch box. The black wire is the negative (ground) wire for the unit, and should wire to the negative battery terminal or a chassis ground. Other wires included with this installation include white, blue, and green. The white wire is used to activate takedown or alley lights. The green wire is used to activate passenger alley lights, and the blue wire activates flashing takedowns.
So, there are white, blue and green. Do you connect them to +12 or ground?

Like I said, the instructions don't tell me what i need to know. e.g Does the RED go to ACC or BATT? Is there any power drain if BATT (on always) is used?

So, as I said "stupid". I made an assumption because this subject has come up before and I have a "little knowledge". Normally +12 is switched and ground can come from anywhere on the body. Vehicles do have specific ground points. Connection to the actual "negative battery" is seldom required. The ground connection is always made. The +12 is connected to a fused source. Whether that fused source can be ON all of the time depends on the design. Some parameter like Quiesent current should be specified.
You really need to ask the manufacturer if they suggest connecting the lights power to a circuit that is on all of the time. The max amount of current the lights draw would also be helpful. All of that changes how you might wire the system. The switch ratings also play a role.

So, I really can;t help you. I can;t even help myself if I was using the info on the light bar I just picked out of my hat.

Need answers to:
1. Can +12 be connected to a circuit that is active all of the time?
2. Quiescent current when no mode is selected.
3. Is the mode selection done by grounding the appropriate mode wire?
4. Recommended fuse size?
5. Does anything bad happen if the mode wire are left open?

I A$$ U ME'ed stuff. Let's say the bar takes 10 amps and I have a 3 Amp switch and you can;t connect direct to the battery. You have to wire it one way. If it can be connected direct to the battery, you can wire it another.
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