Electrical gurus - help rewiring clutch start cancel switch

I totally agree with you on the safety aspect. I meant more about the computer. I wouldn’t run it with a normal on off switch. And a momentary by it self it totally annoying haha. I’d go relay...

I drew up a crude sketch of the circuit I think would work in paint if anyone wanted to visualize what I was thinking haha

 

Sure, I would love to see it.

What I'm not clear on is how you all seem to mention using the beige (+S) and the yellow (-S) to get this working, but no mention of what to do with the pink wire that links into the ignition. Isn't that the wire that sends the signal to the ignition and allows the vehicle to start? What is the purpose of the IG wire in this schematic?

 

I’m thinking the ecm is looking for the beige and yellow to be connected, prob some kind of pull up or pull down circuit. The ign wire only provides power for the circuits in the switch that are lighting the light and holding a “relay” closed until the power is removed. Instead of stuffing a mechanical relay inside the switch their using transistors for that, prob why it’s only 1amp fuse. And then the B/W is just ground for the light and circuitry.

 

I could be way off with all this but that’s what it looks like. The beige wire is prob a 5v ref from the ecm and the yellow is basically ground. So when you put that reference voltage to ground it tells the ecm that switch is pressed and bypasses the clutch switch.

 

Caribe will probably give us a plan once he finds this thread. Or point us to a thread where he already provided a solution.

It feels about the level of a KTJO mod, harder than average but not super hard.

Custom harness with:

Female connector to match the OEM male feeding the OEM switch.

Standard green male switch plug for aftermarket momentary switch.

Standard female plug for a relay (latching makes sense to me) which also feeds illumination back to the switch when latched.

Then, in ktjo style you’d source your own relay and momentary switch and the harness would run about $50 with pointers to her picks for each.

I’d consider it if someone did all that legwork. But I’d also want a nice looking switch which clearly indicates the function. And that seems hard to find as well.

I have some small hope that Toyota might produce an OEM small version of this in the future, maybe for Gen 4 Tacomas if they don’t abandon MT.

 

that would be awesome to find something that doesn't require me to hack apart the OEM connector. I made a custom ch4x4 button that clearly indicates the function, so no problem there. The rest seems like a lot of work for someone to produce for minimal demand, I mean I think I might be the only one lol. I did not find any threads in my searches that indicate someone else was trying to do this. But as usual, you don't know you need it until someone says they make it lol.

 

Your diagram indicates part 90980-12113 which might be this

https://www.toyotapartsdeal.com/oem/toyota~housing~connector~f~90980-12113.html

But I'm not sure if that's the wire harness side or the switch side. It'd be ideal to have both M and F connectors so you could build and test a T harness. You can accomplish the same right now with T taps and then try out your momentary switch. If connecting yellow and beige produces the desired effect on the OEM switch and behavior then you can keep the OEM switch hidden in the dash and use your momentary to get the job done. Possibly even tapping into the pink and ground for illumination if that works too? But I think the OEM switch has some special smarts on the illumination side and that might be more work than you'd want to deal with.

Could you post a larger photo of your switch? Kinda looks like a gargoyle to me in your original post.

 

yep I think this is going to be my plan - I'm going to tap the factory wiring in the least invasive way possible to see if I can get the ch4x4 switch to work. You all have helped me immensely here.

Here a picture I took of the connector, it probably doesn't help a whole lot to get the answer you were looking for.



I was also thinking of using the pink and ground for illumination as well.

 

I'm just throwing this out there.

I have had one car (2001 Saab) and one bike (2013 Ural) that came from the factory with MTs and live starters. My other bike, I modded to be this way. There was zero issue on my end of things. My wife and anyone else who drove the Saab were okay with it.

I'd LOVE for the Taco to be the same. But, there is some thought that the tune is affected by the clutch switches.

 

Unless you can come up with a way to tap the solder pin of the board...

 

LOL just when I thought I had figured out that switch diagram, you throw this in here and I realize I will never understand electrical in modern vehicles.

This is very helpful though, thanks. I am going to try t-taps on the beige/yellow later today and see what I end up with.

 

Look closer, you need to bypass the physical switch, to get the original switch to function correctly. Remove beige wire, connect to added switch. From added switch solder wire to OEM switch (internal board). In essence you'd be placing the physical switch as a remote one.

 

So similar to the garage door opener mod. Extract circuit board. Solder two leads. Connect connectors. Install.

would be ideal to attempt surgery on a 2nd switch or have a source for a replacement ready in case of failure.

 

Sorry I'm slow on the uptake here. If the yellow cable ties directly into that pin on the board, why can't I tap the yellow and get the same behavior? This is probably just a gap in my technical knowledge. I can solder but yeah, I'd want to do it on a spare switch.

It might help to mention that I don't really care about retaining use of the original switch. I'm hoping to bypass it if possible, but retain raw functionality. While also keeping the possibility of going back to the stock switch some day lol. Is that asking too much?

 

OP, since I had to look this one up, seems that a zenner diode allows current to flow backwards “sometimes” and is used for voltage regulation. I assume it’s the triangle facing a squiggle line rather than the regular diodes represented as triangles to flat lines.

So the OEM switch seems to be acting as two switches (DPST) and that may be where we do need a relay to make this happen? The switch near the zenner relay closes to ground while the other switch between the two wires closes to what I assume is +12v?

OP, see if you can find one of these switches somewhere as a first step? Might be possible to order from a dealer and maybe not even insanely priced but who knows.

 

That's what happens when brain is not @ 100%...

 

What about the switch at the top left? Not needed?

 

It's an internal one. I haven't disassembled one...The drawing makes it as an internal relay.