Try this from page 3-16 of the Owners Manual
Switching procedure:
To switch the hazard indicator and horn (chime) operation, push the LOCK *1 and UN- LOCK *2 buttons on the Intelligent Key simultaneously for more than 2 seconds.
. When the hazard indicator mode is set, the hazard indicator flashes 3 times.
. When the hazard indicator and horn mode is set, the hazard indicator flashes once and the horn chirps once.
http://www.nissanusa.com/content/dam...issan-370Z.pdf