How to switch something as soon as power is applied

And whomever modifies the oem wiring voids their warranty on the vehicle.

 

I was going to say that this afternoon!!!

Martin

 

If they are confused by the technology, they would also be confused about modifying their cars circuitry.

I would hack my own car, but no way would I ever modify someone else's car.

 

Afternoon? Should be nighttime on your side of the pond.

 

7:30pm.......I do sleep early, but come on John!!!

 

Lol.
I didn't say you had to go to bed Martin, I just said it was nightime over there.

 

John, It is dark...OK..
It is not late, OK
But if you tell me to go to sleep, I will listen..

Martin

 

Assuming this is a low power function such as a switch into a uC that then controls the engine, then:
1. Small reed relay across the switch with a capacitor in series with the coil.
2. Optocoupler across the switch with a resistor and capacitor in series with the LED. This is for when the voltage polarity across the switch is known, but you don't want to risk a grounding issues.
3. FET or BJT switch with RC delay if you are sure about the grounds.

etc.

ak

 

A better solution is to exp!ain the feature and why they want it. In my Prius you don't even notice when the car starts unless you are paying attention to it.

Hacking the car to reduce its gas milage sounds like a dumb idea to me.

Bob

 

Apart from invalidating any warranty, would such a wiring mod also invalidate the driver's insurance (it would this side of the pond)?

 

No. Not to my knowledge.
As long one is in control of their vehicle, insurance should not be impacted by it. Of course, I could understand a claim being denied after a fire if there was obvious signs of improper wiring, but most insurance companies would likely not even bother to investigate.

 

You could connect the winding of a normally open relay to the start switch and the contacts to the override button. The relay closes every time you start the engine and disables the stop/start system.

BUT, WHY WOULD YOU WANT TO DISABLE THIS SYSTEM?
As BobK said, it would be better to explain the purpose and operation of the system, than just disable it "because my old car didn't have this function".