just ground it to.... ah, wait!
A GROUND //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
a ground = any point of metal attached to the chassis, in wich is connected to the engine block, and that my friend, is connected to your negative battery terminal. or at least i hope it is. becaus if its not. your car wont work //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
just find the wire that the unit uses to ground the circut via the break (shouldnt be hard) and just ground it.
it should be the one that is fishy. a weird connection that dosnt really make sense why it has to be there (should be a long black wire connecting to somthing that has to do with the parking break, but it may be a different color).
good luck. ive never done this //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
but i think thats how it works.