Robotsan
Club Member
So I started here:
You may need to understand a little bit about the wiring diagram that closely matches your vehicle (guessing 240z, but sometimes the USA isn't the same as a UK)
Once you've understood the earthing arrangement and the low/hi wires, throw a volt-meter to confirm it hasn't been modified in anyway by any previous owners.
You can buy relay kits if you're not confident on building your own of course, and as always, the Zclub loves to help
Who does the kits Martin?