My relay is just a garden variety BWD R3177 (commonly used for aftermarket driving or fog lights) I bought at Advance Auto. You don't have to have the ballast installed but if the blue wire is still there use it to trigger the coil of the relay (if you buy the same relay I noted which connection is what on that drawing). If you don't use the blue wire then all that is required is that you find a wire that goes hot (and stays hot) when the ignition is turned on. Feel free to PM me if you have any questions and I can give you my number. Good Luck