Car Stereos: radio power, yellow wires, radio power

Question
i installed an aftermarket dual stereo and now i am trying to hookup a swi-ps universal steering wheel control interface. I have all the wires connected except for the power. I cannot figure out which wires need to be connected to get power to the stereo and the swi-ps. can you help?

Answer
Justin, I always use the same power wires for the accessories as I do for the radio.  The red and yellow wires are the ones I use.  If you need a switched wire, use the red wire.  If you need constant power wire, use the yellow wire.  Hope this helps, Scott