Read ground signal from car switch with Arduino digital pin

Hi guys,

How can I read a ground signal from one of my car’s switches using Arduino’s digital pin?

Thank you.

Just a ground, and no voltage? You can configure the pin as INPUT_PULLUP and connect it directly.

If it's already hooked-up to something else in the car, it's probably 12V when the switch is turned off. Check it with a voltmeter and/or to be extra-safe, use a [u]protection circuit[/u] (a diode and resistor). Or, use a [u]voltage divider[/u] (2 resistors). But but with a voltage divider, still use the protection diode to protected against unexpected voltage spikes.

I've already solved this issue. Thank you.

Thanks for not sharing ;)