I'm doing little project for my car. And I want to connect to wires like brake pedal, neutral switch etc.. many of them are usually left disconnected / hanging wire when inactive, but when are active they connect to the +12V etc... and that's not big deal but some of them when are active are connected to ground.
Doing all electronics myself I will perhaps use pull-ups but when I'm connecting to many wires on my car and many of them are going to the Engine Control Unit and I don't want to harm the unit so I want the transparent way to connect to the wire and detecting ground on it.
I'm thinning about P channel FETs, perhaps that's the answer to my question, but I'm not sure. Do somebody experience with this? Is the P FET good idea, or not?