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How to: Install light switch

Discussion in 'Lighting' started by Skoock, Aug 29, 2019.

  1. Aug 29, 2019 at 8:49 PM

    Skoock [OP] Member

    Aug 25, 2018
    First Name:
    '10 TRD Sport DCLB
    Hey everyone pretty sure this has been covered here but I did some digging and couldn't find it myself so I thought I'd do a little write up on how I wired in my light bar switch.
    I am by no means an expert on the subject and I could've done a much cleaner job but here it goes anyway.


    This switch came from OTRATTW.COM

    This switch requires power from the dimmer/dash lights to light up the lower portion when you turn key. I have already installed an aftermarket head unit so I thought it was easiest to jump from behind there. IMG_20190828_172829.jpg step 1: pull dash apart around stereo and disconnect the HVAC controls and Emergency flasher and remove
    Take out the 4 10mm bolts holding it.
    Tip: caution with the back ones that you don't drop the bolt thru the cracks it's a nightmare to get them out.

    The orange wire is your dashlight and this is where we will be splicing in.
    I made this little jumper at work to easily splice in.
    In hindsight, I should've measured the wire coming out to go all the way to the switch, but I made some of these wires up at work and was too lazy to do it again(also ran low on spade spade connectors)

    Plug the jumper in and run a wire thru the dash to where your switch is located
    I chose to pop this center one out since it was quick and easy.
    Pop out the the little tray that covers the fuses.
    Shove your fingers in and pop it right out. Should come very easy.
    I had to dremmel out the dash a little to make my switch fit. The old one still pops in place fine with the tabs gone.
    Now route dimmer wire thru the opening with about 6" of extra length poking thru
    Next thing you want to do is run a 2wire cable thru the firewall and into the opening for your switch open/close function.
    On the drivers side behind the brake booster there's a small black grommet that you can poke a hole in and go thru it but I accidentally pushed mine thru so you can't see on the picture but it's where the yellow wire (power wire for my sub/amp) goes into the firewall.
    Feed a bunch in and you'll eventually be able to see it somewhere and pull some cable. Route it nicely to your switch and leave 6"
    Since we have power lighting up the switch itself it needs to be grounded somewhere. The top 2 tabs on my switch were both grounds for the LEDs so I jumped them together and grounded it near my park brake. It's hard to see but Its on the same little nut that the green wire is on
    IMG_20190828_185146.jpg so now you have everything you need for the switch so put some female spade connectors on the end of every wire you pulled thru the hole. Double check your wiring schematic and wires
    note what color you used for which side of the 2wire cable. I used white for the fuse side and black for the acc./relay side of the switch.
    IMG_20190828_190443.jpg IMG_20190828_190438.jpg yes I know I used all different ends I only had a handful at the time and wanted to use them up
    After its its hooked up, don't push it in just yet, we have to do the other side of the 2wire under the hood now.

    On drivers side under the hood I mounted my relay on the bolt that holds the fuse box on so I could be close to the battery as well as a good ground. I put a washer between the relay and the fuse box to give it a little extra height so it mounts flush.
    Route the cable nicely to wherever you put the relay and make sure you have enough wire to the battery as well as the relay once you strip down the shield and solder a fuse holder into the (for me) white wire.
    Make sure you use an appropriate fuse for your application/wiring.

    When you've completed your fused wire go ahead hook it up to the positive terminal of the battery. I used an eye and went off one of the small bolts
    Use another female spade
    connector on the black wire and hook it up to the 86 tab of your relay.
    Across from the 86 tab is the 85 where you will need to ground the circuit. I made a small wire to a nearby bolt that has a wire directly to negative terminal of battery.
    IMG_20190826_130336_01.jpg you now have a relay and a switch !
    Reattach your negative cable on your battery and test out your new set up. See if you can hear the relay clicking back and forth when you use your switch. If it works then push it into place and out all your dash back together.
    To power whatever it is you installed the switch for, disconnect the battery again and run another fused wire from the battery positive to the 30 tab of the relay. Run another wire from the 87 tab to the accessory(in my case an LED lightbar)
    And wire it into the positive side of the accessory.

    Now ground the circuit on a good piece of frame without paint on it to the negative side of the accessory.
    I ran another 2 wire cable from the lightbar all the way back to the relay and ground the negative battery cable that attaches to the frame.
    Put your negative battery cable back on and test!

    Anyways hope this help some people out with a couple of the basics. Make sure all your circuitry is going to be thick enough for whatever amounts of amps you're pulling through it and dont skip fuses they are there for a reason !
    Last edited: Sep 4, 2019
  2. Sep 2, 2019 at 4:20 AM

    ctmedic Well-Known Member

    Apr 6, 2018
    2018 TRD OR DCSB
    Nice! Anyone know which wire is a dash light in the third gen?
    tall_paul likes this.
  3. May 17, 2020 at 4:15 PM

    VirusCage Not currently contagious

    Jul 5, 2017
    Allison Park, PA
    2017 TRD Sport DCSB 6MT 1995 Landcruiser 2015 Highlander XLE
    Hood deflector, window vent visors, stainless steps, kb voodoo bedrack, bed cubby cap seals, meso ext fuse cover, meso lower switch panel, 4xhella horns, power tray aux panel, 2wd lo mod, rear FU lights, bed led lights, BPF SKID and Hook, rear view mirror usb power ports, front and rear dash cam, front and rear cam anytime mod, cherry air freshener!
    Thank you so much! I have the same grommet on 3rd gen and was able to use your instructions !

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