Some install pictures from when I did mine
http://www.tta1078.com/scanmaster/
I got +12v from the fuse box, theres a couple of empty slots with +12V ignition key on. Measure where there's some fuses missing and you will find it. Ground I hooked up to the screw close to the fuses (holding on of the metal brackets in place), basicly anywhere metal under the dash with a screw will work fine.