Wire LED bar to high beams?

11048 Views 15 Replies 5 Participants Last post by  Dodgy Dave O'Donnell
I have a LED bar coming to install on my bull bar. I'm wanting to wire it to it's own switch for individual use as well as wire it to come on when the high beams are activated. Is it as simple as just running two power wires? One to the individual switch and the other power wire just tap into the high beam wire on the headlights??
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I think I found what Im looking for. Let me run this by yall and see if it sounds right -

Get a 20 amp relay: Tap into high beam power and run that to pin 86 of relay. Ground pin 85 of relay. Pin 87 goes to the power of the LED bar and pin 30 is the power for the aux switch.
Hmm...Ok. Once the bar gets here I may end up using your setup. I would rather put the minimal amount of stress on my high beam circuit as possible.
If you are worried about the factory wiring at all (or any backfeeding) put a diode on the high beam wire before the relays (so the power will only go towards the relay).
2 questions -

What is this diode you're referring to?

Should I be worried about drawing power from the high beams?
Google diode and/or look on elb for specifics on that inquiry. I don't know what specific diode you'd require but its basically an electronic device which only permits electricity to flow one way.

Drawing power from the high beams- if you are only using it to trigger a relay, I would not worry. If you are using it for anything more than a trigger and/or to power anything other than the OEM high beams, I would worry/not do it at all.

The diode would prevent any random/stray currents (electricity) from flowing back into the high beam wire, which could in theory bugger with the computer/blow fuses, etc. (on the very off chance the relay shorted out, or the aftermarket light itself, or some other random event).
Ok, I'll just use the relay. It won't be used too often so hopefully there will not be any issues.
With the high beam connected to the coil of the relay, the only voltage is from the high beams. A diode would not help as it would need to be placed in series with the relay coil and serve no useful purpose, as the polarity would have to be to allow the +12 volts from the high beams to flow to the relay. With nothing other than the high beam power and ground connected to relay coil there will be no voltages feeding back toward the high beam connection of the headlights.
Ok, so using the diagram you sent me, I shouldn't have any issues. I'll be doing this install hopefully tomorrow.
Ill be using it tomorrow! Can't wait to see how it comes out!
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