Possible ABS disable switch project for First Gen

Hey all,

I'm considering an ABS disable switch for when I'm off road but not in 4L + diff locked. I know this is something that is relatively well documented by @Crom and @DVexile (at least) for 2nd gen's, but the only thing I could find for 1st gen is this thread:

https://www.tacomaworld.com/threads/abs-disable-switch.18347

He references a couple of diagrams - ABS and 4WD, which I've attached. I think only the ABS diagram is really needed.

With no pics and some meh descriptions there, I wanted to draw up what I think is being said and run that by everyone here. (sorry for the crappy Powerpoint diagram):



If that looks right, then does someone have a good recommendation for an ignition switched +12v under the dash? I know I can use the cigarette lighter circuits, but if there's something better, I'm all ears.

Also - if someone's done this and has pics (and I just missed it in my search), I'd love to see the thread!

Cheers

 

Since its a grounding detection switch. I'm not sure if running 12volts to it would work. According to that thread you posted it works.

 

Just curious - how do you know that pin 14 is a grounding detection switch?
Also - that circuit I drew look right based on the description?

 

If you trace wire to the switch, when its closed it completes the circuit to ground. Thats the way i understand the diagram.

 

This^

 

Yep, I see that now - thanks. Does seem strange then that you'd supply +12v to that, doesn't it?

 

I read that thread and his technique seems a little over the top.

I only have an 04 EWD at my disposal atm.

But it seems the easiest way is to to splice pin 26 on the IK2 connector above the glove box, run your splice to one end of your switch (abs kill) and run the other end to a ground point on the chassis. All you would need is a simple SPST switch and it's all done within the cab.

The original circuit for the 4LO detection remains intact, but you trick the circuit into thinking 4LO has been activated when has not. Effective killing ABS.

YOU MAY need to check resistance in the 4LO detection switch and your new SPST switch and add a resistor to make up the difference. But you can try it without a resistor and see if it works.

 

It's worth-while finding a 2000 (if that's your year) EWD if you'd like to start tampering and defeating electrical systems in your truck.

Just a suggestion.

EWD's change year to year.

 

Ah I looked a little further and in my 04 the 4LO detection switch also feeds others systems depending on 5spd or auto and pushbutton and j-shift transfer cases. It also ends up going to the E-locker ecu and the engine Ecu also.

 

Can you post the 04 EWD, so we can see if it's any different than the 00 that I posted?

Those wiring diagrams I posted are from the 2000 FSM, so I think I'm good there.

 

Why not just pull the small ABS fuse under the hood? Simple. Reversible.

 

Don't get me wrong, I love switches as much as the next guy!

 

Don't we all love switches? I considered the fuse pull, but I'd rather something where I don't have to get out and remove screws when I go off road. And, I want to keep the ABS when I'm on-road.

 

Ah I didn't see those there. I'll also need the electronically controlled transmission diagram for your truck and transfer case diagram if you have it.

My EWD is in paperback. And I'm 100% sure they different between the years.

 

ABS 2 fuse pulls right out, no screw.

 

^^^ this. It's the little fuse, not the large one. And if you did want a switch, a simple SPST switch inline with the low-amperage side of the smaller fuse ought to be enough to disable the system.

 

Here's the electronically controlled transmission diagram (note: I have a California). I don't see a transfer case diagram.

 

You already listed it in the OP.

 

So you have an auto w/ j-shift?

 

I've got a manual trans. And yeah, you're right - there it is in the OP