Originally Posted by q9

What I am really asking, is how do I get a relay to turn something on in response to no voltage? It is easy to make a relay turn on by applying power to it - that is simple. All I really REALLY want to know, is how to make some kind of switch that turns on when power somewhere else turns OFF.

Forget the light. Forget the bike. I am simply trying to learn a bit more about this stuff...