Reddit reviews Parts Express 330-075 12 VDC 5-Pin Relay Socket For Bosch Type Relay

It's not that big of a deal.. BUT, I don't know how much wiring experience you have..

Going on the assumption that it's a 300 watt LED bar... That's 25 amps or less of draw.

You need big enough wire to handle the current draw (25 amp+) and a fuse or circuit breaker and a relay. The 300 watt light will pull 25 amps at 12v so using 30 amp relay/fuse/breaker should be enough...

You will also need a switch BUT the switch is only going to be used to power on the relay and the relay will then "switch" the high current from the battery to the lights.

In simplest terms, you can wire it this way....

• Get a 40 amp Relay (30 amp should work too, but I like the 40 amp relay better). You can get them with a wire harness so you don't have to run the wires right "to" the relay. 40 amp relay / Relay harness
  
• 30 amp fuse/breaker near the battery. That wire runs through the fuse to pin 30 on the relay and this will be the source power line for the lights. Here is a 30 amp breaker you can find at your local auto parts store.. It is self resetting. [self resetting circuit breaker] (http://www.amazon.com/Camco-65224-Straight-Circuit-Automatic/dp/B002N59LCS)
  
• Pin 87 on the relay is the output of that power line above and you run it to the red wire on the LED bar (Don't forget to run the black wire on the LED to vehicle ground)
  
• pin 85 on the relay is run to ground on the vehicle.
  
• Pin 86 on the relay is the "trigger" wire for the relay. This wire is what will turn on the light when it gets power.
  
  The Easiest way to do this is tap into the fuse box (under the dash) and pull 12v from something that is "switched power". That means it has power when the key is on. Now, run that tapped wire to a switch and from the switch to the Pin 86.
  
  
  With that simple wiring above, when the key is in the on position, you have power going to the switch, when you flip the light switch the energizes the relay which takes the power from the battery and send it on the the light...
  
  Now, you need to use big enough wire. I'm going to assume you are going to need to run less than 10 feet of wire for the high power (the one on the big fuse). If so, 12 gauge will be fine. You can use 14 or even 16 gauge for the "switch" wire and the ground to the relay to save some money..
  
  hopefully all that made sense.. If you want, we can make the "switch" wiring fancier so you can have lights with the switch and/or with the high beams..

I added a 6v battery and whenever the button is held down a relay switches from the stock 12v to the 12v + 6v in series.

5 pin relay: http://amzn.com/B0002KR9GG

5 pin relay harness: http://amzn.com/B0002ZPUMG

I believe the switch is a Normally Open Momentary Switch I got from Radioshack but there's no shortage of them available online.

Here's a good diagram on how the relay works:
http://www.mp3car.com/imagehosting/12527647e8755a545f7.bmp

Here's a decent diagram on one way to wire it up:
http://www.modifiedpowerwheels.com/forum/userstuff/12vwiz/2009121514639_18vturbo.gif


A few quick photos I grabbed this morning on my way out.
https://imgur.com/gallery/6f2Ph