Yellow wire mod

Is this yellow wire mod worth the risk. I'd like to know more information about it maby how to video.

 

Yellow wire mod for what?

 

It has to with the 4x4 track system. For example my truck doesn't have the atrac. Only LSD. But only in 2x4 . In H4 it uses trac control. In L4 the track control is automatically disengaged. The yellow wire mod is supposed to override so you have trac control in L4. It's weird that toyotas 4x4 system works better in H4 rather than L4.

 

Not sure if you've seen this thread:

https://www.tacomaworld.com/threads/yellow-wire-mod-v-2-4lo-trac.749771/

 

What the hell is TRAC

 

Toyota ridiculous automatic control.

 

WARNING: Long POST

OP I was one of the early adopters of this way back in 2009 on my 4cyl. 5-speed Taco. My journey began in late 2008 after reading on an FJ forum about someone trying this mod on their FJ Cruiser and I became intrigued.

The early 4WD FJs came in three flavors: those with factory ATRAC, and those with ATRAC as an option, and those with just the TRAC feature. However, unlike the Tacoma the FJs with the optional ATRAC were already pre-wired and someone quickly discovered that an ATRAC switch could simply be added and obtain that expensive factory option for just the cost of the switch.

But this was not so for the FJs that came with just TRAC. It was found possible though to get the TRAC feature to activate in 4lo and obtain, what turned out to be, a softer, but very useful, version of the factory ATRAC, someone even referred to it as ATRAC-lite IIRC. The procedure was posted on the FJ forum mentioned.

After extensive PMs with that person I attempted the same on my Tacoma.

ATRAC requires both the programming and hydraulic brake controller capable of fluid pressure sufficient to stop or slow down spinning wheels that occur on the opposite side of the axle. To do so Toyota uses a controller they call a hydraulic assist type. Otherwise the brake controller for those trucks with only TRAC have what they call the vacuum assist type and it can't fully stop opposing wheels.

With this mod I did extensive testing on blocks and rollers. What I found was that on the Taco it was indeed a softer less aggressive version of factory ATRAC. And it worked on both the front and rear differentials. I found that by keeping the RPMs in somewhat of a narrow range in 4lo the effect would strongly launch the truck off the blocks that had its wheels planted on the other side. Otherwise at higher RPMs the wheels would tend to power through the brakes in 4lo, especially 1st gear.

I tried some more aggressive brake pads/shoes in attempt to increase the grab factor on the rotors and further slow or stop the spinning wheels. I special ordered Carbotec (Bobcat) pads for the front and had custom shoes made by Porterfield for the rear. The Carbotec pads were great (and I now use them on my 2014) but experienced nothing but trouble with the Porterfield shoes, along with their extremely poor attitude, and ended up throwing those away and putting on TRD ones.

To summarize this, I could never get the spinning wheels to fully stop but the system worked sufficiently to make a notable and impressive difference -- particularly in snow and other loose material.

To answer your question of whether there is a risk, I do not believe there is a risk but perhaps the normal risks messing with a couple of wires. You just have to be realistic on your expectations. It is not ATRAC or lockers, But I liked it so much I would readily do so again. When I sold that truck I explained to the new owner what had been done and offered to remove it. He was adamant about leaving it alone because of the steep slick driveway, and it works.

In its basic form you will end up with a flashing light and that kind of bugged me. So I wired and installed a factory ATRAC switch to activate/deactivate the 4lo TRAC and a relay to get the flashing off. But for the most part the flashing light may not be that big of deal to others.