3rd Brake Light

Need to wire in 3rd brake light on a topper, pulled headliner and it's a 3 wire plug. Anyone know where I can get the matching 3 wire connector so I can make my own harness? Also it'll be wired into a 2 wire light, which of the 3 wires in the original connector would I use? Not looking to tap into the brake light harness, want to use the stock connector.

 

Why not wire it to your 7-pin trailer hitch? Smartcap goes down to trailer plug and has a harness that plugs right in

 

It's not that easy, or cheap. In my research, you have to wire in some kind of decoder box for each side of the truck. I can't recall the name, and they a couple hundred each.

 

Here's the write-up I did when I wired my 3rd brake light.
https://www.tundras.com/threads/truck-cap-3rd-brake-harness.147874/

Dave, who owned the website has since retired, he had a partner who can be found on TacomaWorld can still make a harness for you.

 

RSI Smartcap and other brands literally sell a harness that plugs in behind the 7 pin harness under the truck. No splicing required, just a plug and play and still allows you to tow and plug in to the 7pin in the bumper. That’s how my third brake light is wired.

 

I see that now. https://www.ezwheeler.com/products/third-brake-light-7-way-interface-plug-in-t-harness-300200 I wish I would've known that before I dropped my headliner 2x and ran wire from the cab to the back of the bed.

 

Same experience as @gesekee19 here:
I added a bed mounted tail/stop/turn LED strip from OPT7 and used their 7 pin to 4 pin plug and play harness here:

$40 OPT7 Easy Connect USCAR 7 Pin to 4 Pin Harness with Reverse Wire, 43"es Trailer Extension Wiring Connector Adapter for Trucks, Pickups, Trailers, Compatible with Redline LED Tailgate Light Bar

https://www.amazon.com/OPT7-Extension-Connector-Compatible-2005-2023/dp/B0CNFZ7TBH
Similar adaptor harnesses are available from other vendors as well.

No decoder box(es) needed.

 

Here’s what I was looking at when I get cap for new truck.
https://www.ggoffroad.com/store/p/tundra-22-brake-cable
Also has cables to move the cameras

 

IF you do exhaust your options and want a quick solution; tapping the driver side tail light is super easy.
If I'm not mistaken:
Ground: White with black stripe
Power: Solid blue

This is how I wired my GFC 3rd brake light through the truck bed liner.

GGoffroad's harness is another great option to get that dedicated line to the 3rd brake light.

 

The aluminum wire going to the tail lights, you are not supposed to tap it, says so in the manual, I guess.

 

You are correct Sir.
Same colors as the 3rd brake light as well.
The passenger side ground wire may be a different color depending on whether the truck has bed lights or not.



Although this is an interesting option..

22 Tundra Brake Light Wiring Tap Cable | Simplify Topper Install - GG.OFFROAD — GG OFFROAD

 

Lilac? Seriously.
If Toyota starts naming wire colors Puce, Chartreuse and Mauve in their electrical schematics I'm going to

 

You're on to something BNB.
It was years ago I read that L stood for Lilac.
But since I have nothing better to do right now, I looked into it.
Pretty sure somewhere in my mind I was thinking of Lavender aluminum wiring..

The L does indeed represent Blue.
Now I need to go back and fix all my posts that I mentioned Lilac...



I relearned something today..

 

whoops...

 

Gen 3 Tundras have aluminum wiring?
That's 2 things I learned today..

 

but purple is darker than lilac. Guess they could have said light purple.... Just takes more space to type