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OEM AUX Light Switch Diagram

43782 Views 16 Replies 13 Participants Last post by  Biff...
Attached is a schematic of how the OEM AUX Switch should be wired up.
Last week I ordered a Switch and pigtail from TRDSource, and while I was waiting for the parts to arrive, I did some research on how to wire it all here on the forums. I came accross some VERY good threads, most notably

NCFJ's Not So Basic Wiring Diagram
WVFJ's Wiring Aftermarket Lights with Toyota FJ Cruiser Off Road Aux Switch

Alot of credit goes out to these guys for the clear and concise information they provided. I decided to throw together a schematic of how the OEM AUX switch should be wired, and print it so that when I install the wiring I would have a handy reference. Figured I would post it.

Here is another breakdown of the switch pins, keeping in mind that the pin layout is labeled while looking INTO the terminals, with the locking tabs on the right:

Pins 1 and 2 are the power and ground for the green LED built into the switch. When the switch is depressed, this little LED lights up and tells you that the switch in "ON". Basically a little indicator. 14-16 gauge wire is fine.

Pins 3 and 4 make up the switching circuit. You have a choice from where you would like your pin 3 supply to come from, and your decision will determine the opperational conditions of the lights. Again, 14-16 gauge wire.

  • If you wire pin 3 from the battery/fuse panel, you will be able to use the AUX lights ANYTIME, ignition on or off. Good choice if you want to illuminate something with the car off. However, if you forget about them being on and go to bed, your FJ's battery is going to be dead in the morning.
  • If you wire pin 3 from a switched 12V source, the AUX lights will only work when the ignition switch is in the "ON" position.
  • Additionally, you can wire pin 3 from any 12V supply wire on the vehicle, but be aware that the AUX lights will only operate when that specific supply wire is active.

Pin 4 is the output to the relay. On the relay, there will be a picture of a little internal coil and switch, and labels for which pins are which. Wire pin 4 of the AUX switch to one of the pins on the relay that connect to the internal coil circuit. The other pin on the relay of this coil circuit should be grounded.

Pins 5 and 6 serve as the gound and supply for the backlight of the switch, meaning that whenever your interior lights are on, you will see the switch lit up similar to the ATRAC switch. As an easy hook up, tap the wire coming from the AUX switch pin 5 to the white/greentrace wire coming out of the ATRAC switch. Then, tap AUX pin 6 to the green wire coming out of the ATRAC switch. 14-16 gauge, if needed, is fine.

A couple more notes, the KC lights and their respective wiring should be in the 8-12 gauge range, considering these lights are rated at 135W. Also, the optional fuse panel is a good idea if you want to keep all wiring seperate from the stock circuits. Tons of good threads about them, too.

Hope someone can use this stuff!
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Heres a thumbnail.


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Looks good, excellent tips.
Nice job Punch!! I am sure that it will be extremely helpful for the guys wanting to use the OEM switch.
Awesome post..............that is exaclty what I was looking for.:)

How long did it take TRDSOURCE to ship the switch & pigtail to you?
Great write-up, punch455!! :bigthumb:

I've added this to the Technical Article section.
Question for punch455. Great post! I understand the diagram a bit more now. And maybe someone can answer this question other than punch...

I recently got the Trail Teams Edition and want to rewire the AUX lights to be able to come on with the push of the button. By reading the post, (correct me if I'm wrong) it says to tap into the green wire behind the switch and connect it to a 12V source, then the AUX lights will only work when the ignition switch is in the "ON" position. Because right now, it will only work with the high beams flipped on. Am I understanding this correctly?
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Can anyone help?
bump.. I too am looking to do what Kindred is trying to do.
I did what you guys are trying to do. While there are probably a number of ways to do it, here are some options. It depends how reversible you want to make it.

Ulimate reversibility
Purchase 12V 30A relay at auto store for $5 or less
Purchase lamp harness Pt297-35070LH $20
Switch harness PT297-35070SH $30

Medium reversibility
Purchase 12V 30A relay at auto store for $5 or less
Switch harness PT297-35070SH $20

I chose the medium option. Remove the radio bezel to get at the switches in the center switch bank. Disconnect the plug from the back of the AUX switch. Wire the new switch harness per directions in this post or original post which is linked to in this post. Essentially you need to tap power off the head/marker lamp. This becomes the power used for the backlight of the switch and power used to latch the relay. Find the connector bewteen the harness coming from the firewall and the harness coming from the lights (located on the driver's side right over the wheel well). Cut the harness on the LIGHT side of the connector leaving you enough to splice the connector back on later if needed. If you dont like this option buy a new lamp harness and cut the connector off it. There are two wires in the lamp harness. These are power and ground. The ground I think has a black stripe. Ground the ground to a body ground. Take the power wire for the lights and connect to the light terminal on the relay. You should have 3 more terminals on your relay. One is ground, ground it. The other two are power from battery, so connect to red side of battery. Last terminal is line from switch. Here is it in words:

Pin 1: Illumination Power for "Lights On" indicator light
Pin 2: Ground for Illumination circuit
Pin 3: Switch Power (taken from Marker Lamp Tap)
Pin 4: Line Out to Relay
Pin 5: Ground for Backlit Illumination Circuit
Pin 6: Illumination Power for Backlight

Pin 3 and 6 are taken from marker light tap. Pin 2 and 5 are grounded. Pin 1 and Pin 4 spliced together and then out to relay.

The only thing you have to be careful of is the red/green trace wire. It looks like there is a diode shrink wrapped in line. I expect this is to prevent feeding power to the switch from the relay. If you swap the Pin 4 and Pin 3 wires it will not work since the 12V switch power that comes from the marker lamp tap wont get to the switch if you try to feed it through the red/green wire. So if you think you got it right make sure you didnt swap them.

RELAY Terminals
Terminal labeled 30 wire to positive side of battery FUSE IT!
Terminal labeled 85 wire to ground
Terminal labeled 86 wire to line from switch
Terminal labeled 87 wire to power side of light harness you found earlier

Now aux lights function by way of switch whenever marker or headlamps are on. That way if you forget to turn them off it also means you forgot your headlamps which will turn off automatically also turning off your aux lights so your battery isnt dead:)

Like I said lots of ways I am sure, but this is a fairly easy, relatively cheap, fairly reversible way.

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Punch455 & WV FJ,

I found both of your posts to be extremely helpful. Everything worked as described.


How do we go about making this a sticky? It's that valuable.
do you know what the difference between the AUX and OFFROAD light switches might be that cause an almost $10 price difference.

I am getting the AUX switch and AUX harness to hook up my ARCO lights from hoping to use the information here to make it work. Thanks.
do you know what the difference between the AUX and OFFROAD light switches might be that cause an almost $10 price difference.

I am getting the AUX switch and AUX harness to hook up my ARCO lights from hoping to use the information here to make it work. Thanks.
Internally different; look at the pics, you'll see that one has a jumper from pin 4 to 5 and no external pin 5. The other SW has no internal connections at all. 3 seperate circuits internally. And, of course, the SW face on each. Other than that they are clones.
I'd like to suggest the following:

Is the housing connector depicted the connector that plugs into the light switch? In other words can I install my Hella wires into the connector to plug into the OEM switch?
tag for future info.
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