Voltage is applied at all times to the horn relay from the HORN fuse through CKT 740 (ORN) to terminals D3 and C3 of the underhood fuse block. When the horn switch is depressed, the contacts close and provide a ground for the horn relay. On luxury models, a signal from the body control module (BCM) or the vehicle interface unit (VIU) will also provide a ground path for the horn relay. On base models with keyless entry, the remote control door lock receiver provides a ground path to energize the horn. When the relay is grounded, the relay energizes and the contacts close, applying battery voltage through CKT 29 (DK GRN) directly to the LH horn and RH horn (if equipped). The horn(s) will sound as long as the horn switch is depressed because the horn switch is directly grounded.