Hi [USER=25523]@beatles2011[/USER], you have a couple of options. You could just wire it direct to a power source so its always on. A bit crude though.
Ideally you only want it powered when the ignition is on, so I would tap the +12v into the radio power, and the black (-neg) can just be earthed on the nearest screw that goes into something metal.
You can test the right wire using a 12v bulb but it should be fairly obvious; red and probably fused.
If you're just using the socket to power devices like phones or sat nav then the draw is very low.
Hth.
Chris.
