Guess I took too long to fix my last statement.
I'm getting confused now, too. I would think that since the orange/blue wire is the hot side, the other side of the bulb should be a switched ground. Just for curiosity, where are you connecting the meter when you say that the black/blue wire has power?
BTW, the relay you're looking for is a "normally closed" type, which means the contact is closed ("on") when the coil is
not powered.