The horn system receives a power supply via the horn relay R2 ; located in the junction unit B1 from the direct battery line via fuse F13 of B1 and maxifuse J/B1 of B5 . The coil for relay R2 is energized with an earth signal when one of the switches on the steering wheel is closed; connected via the clock spring D47 . Relay R2 supplies the high tone horn P10 and the low tone horn P11 .