Wired essentially the same as the single horn except the wire goes to a relay. The switch on the dash is a simple A/B switch. In one position the horn button grounds the single horn and in the other position the dual horns. The city/country switch is about as rare as a winning powerball ticket so I used a three position toggle switch (On-A/off/On-B) under the dash to control mine. The last working city/country switch I saw on ebay was bid to over $200 and hadn't reached the reserve. That was a few years ago so I have no idea what the current market for them is.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.