I'm a novice on this stuff, so go easy on me!
I built a car several years back. I wired in an LED that lights up when the cooling fan is on - but, it sometimes comes on even when the fan is not powered. This generally occurs when I'm driving at highway speeds. It is a 12v DC, negative ground system like almost all modern cars.
I am assuming airflow through the fan is causing the blades to spin the motor enough for it to generate power.
So, I'm thinking I need a diode in the circuit to prevent that from reaching my LED (and presumably the rest of my electrical system too).
Does it make sense that a diode is the right solution?
If so, would I need a rectifier or zener diode?
Is it safe to assume I just need to select one rated to handle the max automotive voltage (about 14.5v DC) and the max current the fan draws (I'm sure it's not spinning as fast as it does when it's powered on high)?
Is the diode then wired inline with the power wire or across the power and ground?
Thanks in advance.