Contour Enthusiasts Group Archives Forums General General Question for electrical guru's

I have underbody lights that i would like to hook up to go on with the existing switch as well as when i un lock the doors. First qusetion is any ideas? Next thing i already tried one way, what i did was go a relay and tried to have that relay activated by the floor lights under the dash, didn't work and here's why. I get it all prepared , everything hooked up except the activation source and power source, both being the light on the drivers side, but before i do i whip out the light electrical tester and test both wires that go to the bulb and here's where it gets confusing. Both the orange and the black have power when the bulb is OFF like a complete circuit would, but when its on only the orange has power. I know my fair share about electronics but this one defeats every rule i know. Any ideas on how to get that realy to work right and possibly and explanation on how the bulbs work and why that "circuit" is like that. Any help is greatly appriciated. Thanx brian