i'm getting cold cathodes

if you don't know what they are, cold cathodes are used to backlight notebook and other low-powered LCD screens. the ones not used for backlights are brighter, smaller, and generate less heat than neon tubes. woohoo!
but i'm having a little trouble finding a ground in the driver's side footwell that i could screw a spade connector to. there are plenty of bolts, but they're all too large..
i have the whole thing right now wired up to the back of the cig lighter. i just used a tap to tap into the power line, and ran a wire down in the footwell. there i have a 10 amp fuse (just in case).