Hidden anti-theft toggle switch for a ‘21 Tundra CM with Keyless Entry?

So, I posted this on FB Tundra groups and got minimal responses there, hoping to get more responses here.

I have an idea, but need to know if it’s a good idea or if it’s a dumb idea. I want to add a toggle switch on the push button start switch on my ‘21 CM Limited. I’m doing as much research as possible before doing anything I might regret, including downloading wiring diagrams and studying them (I used to be an automotive tech, went to school for about 1 1/2 years, plus grew up around cars at my grandfather’s salvage yard/garage until I went back to college to get my Bachelors Degree), so I’ve had practical experience with automobiles of all types for 40+ years.

I’ve seen one “drop in” model that switches out the starter relay with a toggle switch (too expensive), but, that’s not what I want - I’m trying to keep the ability to turn on the truck using my app and the key fob. Most of the toggle switch mods I’ve seen totally switch off the power at the battery, the fuel pump (which I think is dangerous for several reasons), or the relays. This vid (not Toyota) is what inspired me to think about a simple toggle switch spliced between the push button start: https://youtu.be/z140-O486xs

Anyway, what do you all think? I used the following attached pics as reference. I cut and spliced into the grey wire on the 10 pin push start button connector to attach the on/off toggle switch, but, switching it on and off does nothing. The truck turns on with the switch on or off. Maybe I need to use the tan wire instead?




I confirmed the wiring on a post here on this forum



Thanks in advance.

 

LOL

I love it when people post well after they have tried something that didn't work out.

Welcome, and best of luck with this endeavor and throughout the new year!

 

The 2018 and up are really sensitive to electrical changes. Alot of guys on here have ran into issues and blown fuses just doing something as simple as installing interior leds. I would not mess with any wiring in the starting circuit. Just my .02.

 

Thanks for the warning…

 

I went back and undid the “kill switch” wiring (put everything back the way it was) and went back to look through the wiring diagram for the “Smart Key” engine immobilizer and start/stop button. Please see pics for reference. The Black wire is the immobilizer wire - I used my multimeter and connected to SS1 or SS2 and the corresponding pin on the push button (not attached to the wiring connector). This was the only one to register continuity change when depressing the button.

Thoughts?



10 pin start button connector - rear
Tan wire on left rear, grey on right rear



10 pin start button connector - front
Grey wire on left front, tan wire right front

 

Update: I saw this kill switch mod for a Lexus GX460 and think this is the way to go (mostly) for my kill switch. The wires colors and start button connector are different, but, with some more research, I think this is how I’m going to do mine (will use a different toggle switch though).
Thoughts?

 

Let us know your result.

 

So, I decided to try out the DIY similar to the vid posted above and I can definitely say it’s a NO GO. I did everything exactly the same as the vid for the GX460, except use a toggle switch instead of a reed switch. The relays actuated, BUT, the truck would not turn on with the toggle in either position. So, off it went ( too the whole damn thing a pasty and back to “original”), and the truck is back to working, EXCEPT, now I have the “refuel” light on in the dash. Ugh. All I wanted was a kill switch when I have to travel and leave my truck in a “strange” parking lot. But no… this won’t work. At all. This is beyond the skills of a former automotive tech who stopped working on cars in the late 2000’s and am now only an occasional tinkerer with my wife’s car and my truck. I guess that’s all she wrote for this act of futility.

 

Least you gave it a shot.

 

I unplugged the neg batt terminal for about an hour after posting this morning… it reset the ECU and the “refuel” light turned off. Yay.

 

Thanks. I really, REALLY wanted this to work, but, alas, it didn’t.

 

Yeah. Kudos for trying.