Current is distributed to terminals 2 and 3 of the horn relay through CKT 1540 from the 15 Amp Horn fuse. When the horn switch is pressed terminal 1 of the horn relay is grounded through CKT 28. The switch side of the relay then closes which allows current to flow through terminal 5 of the relay. Current then flows through CKT 29 to the horn allowing the horn to sound. The horn itself is grounded through CKT 150.