I have an XM radio I need to install in my truck. It gets power from the cigarette lighter socket using a 6V adaptor. I don't want to have the power cord exposed, so I was going to wire an additional female cigarette lighter socket and hid it behind the dash. I don't want to tap into the factory wiring for the cig. lighter/12V access. sockets in the dash because they are always hot. I need a source that is switched to the ignition so that I don't have to remember to turn off the XM radio every time I park the truck. Any suggestions? If I did a poor job describing what I'm trying to do, please let me know.