VSC Off, ATRAC On Mod complete!

[Ryco4R]

it seems the vast majority of folks are wanting/doing this mod for snow driving: pulling out into a slippery intersection (i.e. some wheel spin) kills the throttle and leaves you vulnerable to oncoming traffic. i experienced this earlier in the week, and although there was no oncoming traffic, it was very disheartening. i'd like to get this done before the real weather hits, plus i'll be driving to CO for a month this feb. the off-road benefits are that you dont have to lock the diff to kill the vsc, which as i type this, equates just as well to on-road driving where you will be going around corners (not great w/ diff locked).

eagerly awaiting C3Flyr's response...

 

[SSt4r]

This was great. After waffling for months on spending the extra money for factory switches, I finally decided to do this. For the record I have a 2005 4WD V8.

A slight variation:

After having the dash apart & running the wire to the 4wd control ECU as shown, I noticed an unused connector (blue) on the left side of the dash where the switches go. I tracked it down in the wiring diagrams & discovered it is the connector for the "Trac Off" switch [which I believe is for 2wd only variants]. Being curious I looked at the diagram further & realized that the red with white wire for Trac Off runs to the skid control ECU. The red with blue wire that we tap at the 4wd ECU for this modification ALSO connects to the skid control ECU. Same wire. Hmmmm...
So, I purchased a used "Trac Off" switch and for ha ha's, I connected it to the empty blue connector & (breath hold...) tried it. Nothing. I confirmed that on my 4wd, the "Trac Off" switch has no effect on the condition of VSC (or any thing else that I could tell). Now on the 2005, the skid control ECU is in the engine bay at the brake fluid reservoir (I think its under the dash on earlier models???). I confirmed that the red & white wire in the connector (at position #43) at the skid control ECU is in fact the same wire at the blue connector behind the dash. The wire I needed to tap (red/blue) was at position #27 of the same connector. I simply cut the red/white wire close to the connector & tapped it into the red/blue wire a couple inches from the connector (I had to remove some of the loom & tape to tap it there). I sealed the connection (heatshrink tubing) and re-taped the harness & replaced the loom.
So now I have a factory looking switch all connected to work the VSC off mod. The ground needed & illumination wires are already in the blue connector so the total installation was VERY easy!

But wait, the "Trac Off" switch is only a momentary switch you say. Well fortunately some one else had shown (I think on this forum - will research it) how to convert a momentary switch into an on/off one. Not that hard. Briefly if you can take apart any on/off switch, you will see that it has a very thin wire across it and a slightly thicker "Z" shaped (kinda "Z" shaped anyway - maybe describing it as two offset bends is better?) that rests on the first wire. Simply duplicate these pieces (I used two thin pins of the same diameter). It is important to DUPLICATE the "Z" shaped pin as closely as possible - a little trial & error. Remove the white plastic piece inside the momentary switch (you will see the on/off switch does not have that piece) & put the switch back together. Voila! An on/off "Trac Off" switch.

Now the purists will say that it's only turning the VSC off & not the traction control off. I know; I would have preferred to use a "VSC off" switch but I know what my switch does if I use it. For the "plug & play" ease of installation this slight discrepancy was worth it to me.

A word of caution if anyone proceeds with this. I originally used copies of the 2003 wiring diagram. For that year, the red/blue wire at the skid control ECU is listed at position #3 & the red/white wire is at #26. The 2006 wiring diagram mirrors what I found on my 2005 (YMMV!). Please confirm what wires you cut / tap beforehand! For mine, on the skid control ECU connector #41 is light green, #42 is RED/WHITE, #43 is also RED/WHITE, and #44 is white/green. With the connector disconnected from the skid control ECU check for continuity between the red/white at #43 & the red/white at the blue connector for the trac off switch (WITHOUT the switch connected to it).

Thanks go out to CJ3Flyr & Andries (at T120) for giving me the courage for this!


In the 1st picture below is the connector for the skid control ECU. To disconnect it, pull the white locking piece forward (about 1/2 way in photo) & pull the connector itself easily toward the fender at the same time.
In the 2nd picture my fingers point to the red/white wire I cut (connect the other end - not seen here - to the red/blue wire) & the red/blue wire to connect/splice/solder it into, the one that runs over the screwdriver in the picture NOT THE BLUE WITH RED AT THE TIP OF THE SCREWDRIVER. The black cover that snaps on (you can see it in the 1st photo) has been removed.
The 3rd shows the switch I used that plugs into the factory harness without modification to the plug or wiring.

 

[martini]

But wait, the "Trac Off" switch is only a momentary switch you say. Well fortunately some one else had shown (I think on this forum - will research it) how to convert a momentary switch into an on/off one.

Here's where the instructions are: http://www.toyota-4runner.org/4th-gen-t4rs/71144-part-number-factory-vsc-off-switch.html#post606651

 

[SSt4r]

That's it exactly! Thanks martini. Gaterose made it very easy.

 

[00328]

SSt4r - I am wanting to do this mod and also have an '05. You didn't happen to take any pics of your install, did you? I hate to go cutting wires unless I'm sure I know exactly what I'm doing......and I don't know what I'm doing. Pics would really be helpful.

 

[SSt4r]

00328, I just added pictures above, let me know if that helps or if you need something else. This taps the same circuit as this thread originally described; I just tapped the red/blue wire in a different location in the truck for my version.

 

[00328]

Awesome pics man! Thanks.
I didn't realize the connections were made in the engine bay.
So you didn't have to run any wires through the fire wall and the blue plug is sitting right there behind the dash?
Did you have to modify the trac-off switch at all?
Looks like a very clean install.
Thanks again, very easy to follow.

 

[SSt4r]

I didn't run ANY wires through the fire wall. The red/white wire in the picture is also in the blue plug & yes, the blue plug is right in the dash - with the center diff. lock & a couple others.
I DID have to modify the trac off switch. It is momentary (ie: doesn't stay on) & I made it on/off - see "Martini"'s link above to convert the switch. Or just use any on/off switch.

 

[00328]

Got it, Thanks.

 

[00328]

One other question if you don't mind. You may not know this, but does that blue plug fit the VSC OFF switch also?

 

[SSt4r]

I don't know if the VSC off switch would fit or not, maybe someone else can chime in? & I'm pretty sure it too is momentary (and can be altered).

 

[00328]

Yeah, it is a momentary switch also. I'm just wondering if it is a 6 pin switch like the Trac off switch to accept the blue plug.
I'll do some searching and see if I can pull up a pic of it.

 

[00328]

Ok, finally got this mod done. Did it exactly like SSt4r did.
Got the switch and modded it to on/off. Not hard to do just a little trial and error. Found the plug sitting right behind the lower dash panel and it plugged right into the switch.
Switch lights up just like the other switches, looks completely factory. :bravo:
This was a very easy mod.
Now for some ice and snow so I can test it out.

 

[RallyeFan43]

Definitely looking forward to doing this mod. The VSC can be a great help at highway speeds, but a PITA most other times in snow.

SSt4r, just to clarify, does your method of doing this mod work the same as CJ3Flyr's. As in the diff lock light will still be lit when you have the VSC switched off? That, and having to put it in 4Hi then back into 2Hi in order to get it to work in 2WD? It'd be nice to not have to do that each time you got in the truck, as opposed to simply pushing a button.

If it does act the same way, is there no way to mimic the setup of the factory VSC OFF that came in the '08+ models? It would be awesome to just push a button and have the VSC diabled in either 2WD or 4WD. I don't have a thorough understanding of vehicle computer systems, and what I'm asking may be much more complex than I realize. I'm just curious.

 

[SSt4r]

Yes, it works exactly the same as CJ3Flyr's; I tapped the same circuit he did but just in a different location (at skid control instead 4wd ECU).

I don't have a 2wd option (I have a V8), but the method he described for VSC off in 2wd should work the same.

Unfortunately, I think this is as close to duplicating the VSC off in the '08+ models. I believe in those it's handled in the computer itself (different unit).

Included below is my "modified" wiring diagram of how I proceeded.

 

[00328]

Those diagrams mean nothing but mumbo jumbo to me. It was your pics that really made it easy. Thanks for taking the time.

 

[chaz]

00328, did u try the vsc switch & does it work (plug in like the trac) without having to be altered?

 

[00328]

It plugs right in, no problem. Just need to convert it to off/on operation.
Pulled off the lower dash and the connector was right there next to the 4X4 switch.

 

[chaz]

thanks

 

[Koz]

I can see this mod being useful during low speed, low traction conditions. I have a switch on my IS to disable either traction and/or VSC and it does come in handy under certain situations but I do recommend you being very careful when it is activated while driving during on-road or descending off-road. It is annoying when you need to accelerate and the engine cuts out but it's cutting out to prevent a Batman turn. Also when descending off-road on very low traction ground things could get very ugly, real quick, if you need to keep your speed down. Nothing is scarier than going sideways down an off-road trail. There is a time and place to disable VSC, just be extra careful when and where you do it. Remember VSC can pulse one wheel at a time to keep you going straight, this is IMPOSSIBLE for a human to do.

Koz