its general view on relay pero pareho lang sa busina application.
HTH
take note yung "famous Bosch relay" nya sa pic ay iba sa famous bosch relay sa pinas. double throw relay yung sa pic nya, yung madalas na available sa suking auto supply dito sa pinas ay single throw relay... a single throw relay has two "87" terminals(pwede one terminal for each horn gamitin mo) and use a true guage wire yung #12 na wire pwede na.