One problem related to horn assembly has been reported for the 2012 BMW X5. The most recently reported issues are listed below.
Car was parked in driveway, not running or turned on. Horn and wipers started going off. Went outside to vehicle, tried to disable. Smoke started coming out from behind the dashboard (passenger side). Could smell electrical short. Smoke followed by flames, entire dash area caught on fire, by the time fire department arrived and put it out.