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I thought I did understand electronics slightly but today I'm no longer sure...
In my car there is a light module with an ordinary lamp.
A diode (just a 1N4007) is mounted anti-parallel over the lamp.
Why is this done ?
(if you want to should "voltage spike protection" than Why is it mounted over the lamp and not over the voltage spike source like a relais ?)
Did you ever find it in your car ?

PS,
This question is based on the assumption that for some people their car is their home and so it is part of their domotica

That way you can detect if the lightbulb is broken or not.

AshaiRey wrote:That way you can detect if the lightbulb is broken or not.

Interesting.....
so to do this test,
some electronic-device in the car should put a negative voltage on the line
to test the difference between
1) lightbulb broken
or
2) fuse broken
So if this is correct,
which device/unit/component is putting the negative voltage on the wire ?

PS
We should implement this in hour home systems also