Need to a find the "READY" wire or Equivalent

I'm working on another custom electronics project for my new car. I need to find the simplest way to detect between if the car is ON/READY or off, or IGNITION mode.

In my other 2012 prius, I was able to do this by simply building a circuit that monitors the 12-volt rail, and if it was > 13.6 volts that is a solid indication the car was ON in ready mode.

This is not working so well in the Prius prime, however, not sure why, but it would seem that the 12 volt side of that car tends to fluctuate when READY to both >13.6 and <13.6. Is there a definitive voltage range on a prime when READY? Can the led signal wire in the dash that lights up the green READY light be accessed without a major teardown of the dash?

Another acceptable solution to my issue would be if I could access the wire that goes HOT when you press down the brake with the smart key in the car but have not yet pressed the PTS button, which shows up as a "key" graphic in the centre screen. I assume some wire in that car someplace must trigger this graphic?

In my 2012 there was a green LED that lit up in the PTS button itself, but that is absent from this model's PTS button.

 

Very helpful. Do you happen to have the pin out or data sheet for the 7 wire brake light switch? This one you posted seems to cover the 4 pin one...or Im reading it wrong. Im looking for the 2018 prius prime plus.

 

So far I can tell, black is +12v along with Tan. Green is brake lights, Red is brake press. Not really sure what any of the rest do. Im trying to emulate a brake press via relays and tap-ins and or make/break cuts to these 7 lines. I pretty much got it by opening black, red, and green from the brake light swtich, and closing red to black. I dont think this 100% correct tho, as Im often getting errors with the pre collision system and cruse control.

Plus Im still struggling with a way to detect when PTS is ready for push, and a reliable way to detect if the car is indeed in READY mode.

 

I can't get into too much technical detail just yet, waiting on some patent stuff first. But in a nutshell, I invented a secure way to remote start Toyota PTS cars with full take over. No shut down on door open or brake press (if you have the fob in hand). Im trying to adapt it to work on the prius prime. The two big challenges are finding a reliable way to know if the car is in ready mode or not. And to find an equivalent of the green led in the 2012 PTS button. A possible answer to that is knowing if the car is in IGN mode vs READY mode, but it's just an idea for now.

The good news is, I think I may have it fixed right now. By putting a tighter clamp on the 12-volt battery range, I think I got my detector to work. It seems the ready voltage is only 14.1 max (at least so far) and the off is something much closer to 12.1. I set my trigger to hit at 12.6. Too early to call it done, but it's working at the moment.

Thanks for your help.

 

If you're talking gas engine on only, yes find a voltage wire driving the coil packs on the low side. Or my maybe on the even on the spark plug side (if you know how to deal with that high of a voltage). If you mean just READY mode, ICE on or off but still ready to drive, I can help you with that. In 2012 the simple way is to just monitor the 12-volt battery side. anything > 13.5 the car is on, less its off. If you need a circuit that will do that, message me.

What project are you doing? Sound like we might be able to help each other.