I drive a 2013 IC CE, twice this last week the horn has gone off by itself. Both times the bus was unattended. The temperature was below 20 degrees. The horn stopped by itself after almost 30 minutes the first time . on the second occasion it was disconnected. When it was reconnected 30 minutes later their was no problem. Any suggestions as what is causing this problem. Anyone, Anyone.
double check that the cage that the horn pad sits in isn't bent down from someone hammering on it. use a crows foot pry-bar to lift the cage a bit. Even with the new part number the horn can still go off by it's self when cold if the cage it clips into is bent down.
Do you have a 'child reminder system' on this bus? Try disconnecting that and see if the problem reoccurs. We had a few of those 'bus-scans' short out and randomly blow the horn.