65 Dart Horn Problems

That's a good question. I haven't had it together and connected to the horn without the wheel in place since I replaced the bad relay. I've just been disconnecting the relay and horn while I work on the wheel/turn signal/horn switch. Would that tell me if the problem was in the switch or the wheel making contact before the switch? BTW I watched a youtube video on using a multimeter and am going to buy one today. Question, after the wheel and horn switch is installed there's a green wire that connects to a paddle on the switch. Is that ground, or positive?