pull out the radio and follow the ground and power from the "plug in" behind the radio.. i believe the power is red and runs to the fuse box on the left side of the dash and i believe the ground is black and might have a solid white line in it and it goes to a screw that holds the dash in place if im not mistaken, it can be seen with the radio out.
that is from what i remember when i had to replace my radio long time ago.
what do you need to know for?