Wiring auxiliary lights to independent switch

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
I found lots of threads about connecting bumper-mounted aux lamps to the existing fog light switch, but nothing describing what I want to do, which is to connect aux lamps to a separate, independent, factory switch.


Here's what I have:



  • 1 pair of LR Safari 5000 driving lights mounted to factory brush guard
  • 1 aftermarket wiring kit with relay, grounds, and integrated switch
  • 1 spare factory fog light switch with harness


I want to connect the wiring from the lights to the spare factory fog light switch. I will install the spare switch in the blank space on the dash alongside the existing fog light switch.


Here's the issue: the harness coming out of the factory switch has 4 wires:

  • red
  • blue
  • black
  • blue/black
The wiring for the aftermarket kit has 3 wires running to the integrated switch:

  • yellow
  • red
  • black
I can splice the wires from the kit to the factory switch but I don't know which color wire from the aftermarket kit connects to which wire on the factory switch harness.


Has anyone done this and can tell me "yellow goes to blue, red goes to red, black goes to black, blue/black hangs in space and doesn't do anything"? Or whatever the correct combination is?


Also, where is the best place on the firewall to pass the wiring through? Is there an existing spot behind the dash on the driver's side that I should look for?
 

CORover

Well-known member
Jun 11, 2007
745
65
Colorado, USA
Or you can do this; Switch Pros SP-9100. A little pricey but does everything you need and gets rid of some wires and components and keeps all the switches in one small place. I just went through this ordeal on my "rig" (sorry) and this was the best solution I could come up with. I had switches, relays, connections and wire everywhere. This sill simplify the whole mess.


I did get everything hooked up using factory switches but it was very time consuming and is still a mess. For the switches, I had to use the electrical diagram in the Rave and make a few educated guesses on inputs and outputs of the switches.
 

BarryO

Well-known member
May 15, 2018
98
7
Bend, OR
Here's the issue: the harness coming out of the factory switch has 4 wires:

  • red
  • blue
  • black
  • blue/black

According to the RAVE electrical manual, the wires for that switch are:
  • black - ground (for the two indicator lamps)
  • red/brown - power for green indicator lamp
  • blue/black - +12V power input
  • blue/purple - power output (i.e., gets 12V when the switch is pressed in)
 
Last edited:
  • Like
Reactions: pdXDisco97

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
Thanks for the info from RAVE, that is helpful to know what all the factory wires do. The diagram that came with the Hella wiring kit doesn't say what the 3 wires do that connect to the switch. Here is the link to the diagram. The kit I have is shown at the bottom of the first page: spotlight harness. Will the Hella wiring setup (black, red, yellow) be compatible with the factory 4-wire harness?
 

BarryO

Well-known member
May 15, 2018
98
7
Bend, OR
Does the aftermarket switch light up when turned on? If so, my wild ass guess as to the wiring is (i.e., don't blame me if you burn up your rig's harness :) ):

  • red - +12V input; check for continuity to the red ring connector with an ohmmeter
  • black - ground (for the internal indicator light); check for continuity to the black ring connector with an ohmmeter
  • yellow - +12V output; gets 12V when the switch is closed. Check this with a voltmeter

If all this checks out, then you could hook it up follows. You could put .250" male connectors on the fog light wires and just plug them into the female connectors on the aftermarket harness:

  • black --> black
  • blue/black --> red
  • blue/purple --> yellow

Hook the red/brown wire to the indicator lamp power on another switch, if you want the switch to light up green at night
 

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
Thanks, this is useful. Electrical is not my strong suit. I haven't hooked anything up yet, but the Hella switch has a power indicator LED on its face so it should illuminate when the lights are on. I'll give it a go and see what happens.
 

best4x4

Well-known member
Mar 1, 2015
595
72
Beaumont, TX
Momentary fog light switch or the aux light switch is useless. Grab a cruise control switch, slap the fog/aux switch cover on it, and now you have a latching on/off switch. You can tap into the dash lights for nightime illumination, then you can either file down the plastic hump to make any dash plug fit or use a c/c switch pigtail. Then connect the rest to your aux relay. Bingo factory look with aux wiring harness.

Also I highly recommend grabbing a cheap digital meter. It makes guessing the 12+, ground, and illumination a breeze.
 

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
What do you mean by "momentary fog light switch"? The extra factory switch I have is a duplicate of the front fog light switch that does "latch", by which I assume you mean that when you push the button it clicks and holds a depressed position until pushed again to release/turn it off. I do have a multimeter and will use it to test the functions of the auxiliary harness wiring. Thanks for the suggestions and patience, this is my first attempt at wiring something more complicated than putting a 1995 RRC analog dash clock into my D1.
 

best4x4

Well-known member
Mar 1, 2015
595
72
Beaumont, TX
Yeah with a D1 switch you’ll be fine. Just so many people grab the D2 switches & complain when it doesn’t latch. One of my favorite mods on my 98 D1 was the RRC Analog clock!
 

JUKE179r

Well-known member
Sep 14, 2016
761
95
Suffolkshire, UK
This wiring diagram is what I used to wire up my front aux/fog lights:
28488d1451362581-aux-light-failure-dii-driving-lights-kit-modified-relay-latching-switch_zpsa54b0c8e.jpg
 

Tugela

Well-known member
May 21, 2007
4,754
562
Seattle
Okay, wrapping up this thread. I finally finished the project. Everything worked out great, only the color schematics mentioned above were wrong. And I forgot to write down the correct combo, so I can't even give the correct information. Here's a photo of the whole enchilada before I reinstalled the switch bank.


43291488_1650773748360196_5504653300298940416_n.jpg
 

Inlimine

New member
Jun 12, 2019
1
0
Los Angeles
Anyone have a lead on the wiring harness that LR used to sell for the front auxiliary lights? I believe it's part number STC50039. I'm in search of one to install some PIAA or ARB lights up front using the Auxiliary 2 switch that fits to the left side of the steering wheel on a Discovery II.