How To: Replace Your OEM Fog Light Switch with an OTRATTW Switch

Alright guys and gals, it has taken me too long and for that I apologize but here is the writeup on how I replaced my stock fog light switch with an OTRATTW one for a uniform looking dash.

DISCLAIMER: Do this mod at your own risk! I accept no responsibility for any damages to your vehicle while attempting this modification.

Side Note: I was not able to get the top indicator lamp to work. The Tacoma uses a ground trigger to activate the fog light relay, thus there is no electricity in the circuit to activate the light. You could wire in a relay and make it work, but that was more than I was willing to do as the indicator lamp isn't a big deal to me.

First, disconnect the negative side of your battery to ensure you don't shock yourself or short something in the truck. **I forgot to do this and spent 2 hours trying to find a blown fuse that controlled all of my exterior marker lights and dash lights.**

Next, it's time to disassemble the dash and fit the new switches. I followed BBYE V8's writeup linked below for that part.

http://www.tacomaworld.com/forum/2n...-contura-v-carling-stock-switch-location.html

Side Note: I moved my inverter switch to the bottom row of buttons. To do that, I had to modify the socket for the switch where the lower blank was. Just cut a small groove on the right hand side of the new socket and the switch will slide right in. I also had to cut a bit of electrical tape behind the dash to get the slack in the wires to relocate the switch.

On to the meat an potatoes, the wiring.

After you pull the OEM fog light switch out you will see 4 wires on the connector.

White with a Black Stripe: Switch Ground
Blue: Fog Light Trigger
Green with a White Stripe: Dash Illumination Ground
Green: Dash Illumination Positive



The OTRATTW switch you ordered will determine the final pin-outs of your connections. Use the wiring diagram provided with the switches you ordered. It will look like the image below or you can go to http://www.otrattw.net/wiring-diagrams.html and get yours.



What ever your pin-out, you will want to use the following connections:

White w/ Black Stripe Wire --> the pin labeled "From source with in-line fuse"
Blue Wire --> the pin labeled "to your relay or accessory"
Green w/ White Stripe Wire --> the pin labeled "Ground for the lower lamp"
Green Wire --> the pin labeled "Normally connects to your dash light circuit"

I ordered the V1D1JHHB switch so it ended up like the picture below.



You may also need to extend the factory wires like me. I recommend using a lower gauge (thicker) wire (I used 18) than the factory wire. Make sure that you keep track of what wire is what if you don't have different colors. I used two green wires as you can see, but I marked the ground side with strips if electrical tape. (Far left hole is the fog light wires in the picture below)

I also recommend soldering on the female quick disconnects to ensure a strong physical and electrical connection to the switch.



Once your wiring is prepped, plug in your switches and reconnect your battery to make sure that everything works. The lower light should illuminate when the dash lights are on and fog lights should work normally.

If everything works out, it's time to reassemble your dash and enjoy your new switches while you crack open a beer with your dad who helped a lot by working on a CB install at the same time.





This is my first writeup on here, so if you have any questions please feel free to contact me. I'll be glad to help in any way I can.

 

great write up!

 

Any particular reason the top LED wont work? I thought LED's only needed a flow of electrons to light up.

 

I'm not sure, in theory you are 100% correct. The only thing that I can think of is that since the fog light relay is activated by closing the ground side of the circuit, it puts the LED in the switch at the wrong polarity. I was able to get the upper LEDs to work on my CB and Bumper light switches by feeding a positive line through them. I disconnected them after I couldn't get the Fog Light switch to work.

 

You may have mentioned it but I only glanced through. The otrattw switches don't fit without modifying the hole.

Since the white/black wire is ground shouldn't it be on pin 8? This should complete the circuit for the switch light and still turn on your fogs. If that doesn't work try switching pin 3 and 8 (switching the polarity).

Otherwise great write up!

 

You are correct, the hole needs to be modified. I linked BBYE V8's writeup on the physical install at the top of the OP.

I did try putting the white and black wire on pin 8 and swapped the polarity like you mentioned. All that did was illuminate the upper LED when the fog lights were off. This is because the circuit is always looking for the shortest path to ground and when the switch is on, a dead short has less resistance than the LED does.

I think the easiest way to get the upper LED to work would be to use a relay to provide a +12v to the LED when the switch is on.

 

Right-o. Sounds like you got this handled

 

after digging and reading through lots of sites, i talked to the otrattw switch people, you need a upper and lower independent led switch. i have one on order, we'll see what happens.

 

Some guys use a dremel and cut out the slots to make an OTRATTW switch fit there as shown in these thread.
http://www.tacomaworld.com/forum/lighting/315153-there-switch-fits-here.html
http://www.tacomaworld.com/forum/lighting/229562-help-getting-otrattw-switched-fit-2012-taco.html

Others use the blanks to put in the small rocker switches.
http://www.tacomaworld.com/forum/2nd-gen-tacoma-marketplace/246690-09-switches-blanks.html

 

Could you by any chance tell me where the fuse was that you blew like you mention?? Just did the same thing...

 

I think there is a little confusion going around on how this switch works. I will go ahead and explain:

#8 and #7: These are meant to be the ground for the leds. U can jump the Green/White to each of these pins. This wire actually controls the leds to dim with the dimmer switch.

#6: green wire that was shown above will be connected to this. This will send 12v to the lower led when u turn the dash lights on. #7 again is the ground for the lower led and will have the Green/White wire connect connected to it so the dimmer switch can dim the light.

#2: incoming 12v to go to relay switch

#3: wire going to relay switch. When u activate the switch #2 & #3 will then be connected together or "closed" and send 12v to the relay to power the light.

The upper led gets its 12v power from #3 when the switch is active. The ground is the Green/White wire which is jumped between #7 and #8.

Any questions.

 

Check out my diagrams for the aironboard switches and see if they can be applied here.
https://www.tacomaworld.com/threads...n-switch-for-fog-light-factory-wiring.407092/

 

Yea like that but does that light the light when the switch is turned on? What if you put a power wire to pin 3?

 

No. You'll need a switch that has independent illumination for the "on" led. The stock fog light relay is a switched ground not 12v so the led will not come on. Pin 3 is your "outgoing" ground from pin 2. You can't put 12v there, the stock fog relay won't trigger.

 

I know it can be made to work. I think you'd have to turn the LED around and move the W/B and Blue wire and add a power wire. I did it with an aironboard switch here https://www.tacomaworld.com/threads...n-switch-for-fog-light-factory-wiring.407092/

 

You need a switch from OTRATTW that has upper and lower independent leds. There's no where on that diagram posted where you can add anything to get that upper led to illuminate. If you do, your stock fog relay won't trigger. Like I said, the stock fog circuit uses a switched ground to trigger it, so your pin 2 is actually a ground. Normally that would usually be 12v to send to your relay. That is also where the upper led gets it's 12v from when the switch is on. For me, I just bought the correct switch.

 

The wire coming from the the coil side of the relay is "hot" looking for ground. No need to add another positive source to get lamp to illuminate.

 

Here are the diagrams of what I am suggesting. First the OTRATTW v1d1j original diagram, then the updated one to work the upper LED (D1) with the fogs. The updated one I added the foglights to the diagram for better clarification

 

But then the voltage drop across the LED changes the voltage to the relay. Is this not an issue?