If you've got 4 relays and a bit of spare time you could give this a shot. My roommate built mine a new brain with existing wires plus a 12v constant run from under the dash (ignition I think). That feeds to a open relay at rest, so you won't be draining the battery while you're parked. We also installed a fuse in line to prevent things getting too hot, but I've had this "mod" for a couple months without fail.
If anyone sees something scary in there, let me know cause I haven't got the mind for this stuff. That's what the roomie is for.
