The horn in our M3/4 has become unreliable -- usually works fine, but sometimes not -- esp. when cold [PA winter here]. When malfunctioning, repeated pressing all around the center horn/airbag pad may get an occasional toot, but not for pressure in any particular location. My mechanic [a bimmer specialist] removed the airbag & cleaned horn contacts, but the problem remains. He suspects we may need a new steering wheel [ouch] but I'm not convinced. Why does is it usually ok?! Relay perhaps? Anyone out there had similar problem? Ideas?