Re: dashboard lights
The light is a warning light to tell you one of your lights is not working.
The system covers all outside lights except the indicators. If it isn't obvious which light is out try a process of elimination, if it only comes on when you brake, it is a duff brake light, same when reversing. If it only comes on when you turn your sidelights on, but it looks like the head and taillights are on it is goiung to be the number plate illumination lights.
Replacing the bulb, or hitting the offending light hard tends to fix it.
The system is know to throw a wobbly for no reason at all.