[bigislandboxster]

You should get a negative ground wire with the harness on the Alpine, just hook that up to any common grounding connection on the car....If you can't find a bolt to attach it to under the dash, extend a wire to one of the bolts in front of the battery compartment, thats where mine is grounded to....If you have to extend it, let me know, it can be frustrating getting wires past the firewall if you don't know where to look.

Also, as a warning,when you take your old head unit out you'll see a green wire connected to a male terminal on probably your right side of the mounting sleeve. This is part of the anti theft system, if you leave it there and put another head unit in there, it'll possibly read that the unit has been stolen, and will not fully arm. Take the female end off and tape it up and tuck it somewhere where it won't come into contact with any metal parts.

Lou