What's this humming sound coming from behind the dashboard in my L322 FFRR?

It happens periodically, although only about 2-3 times per year. It always has done on and off over the last 3 years of ownership but it doesn't seem to cause any problems - Switch off the engine, it eventually fades out - Re-start the engine and it's completely gone! - Bizarre!

It's the speaker that gives off the bongs and bings and clicks for the indicator sounds. Has happened on mine a few times (as well as a BMW instrument cluster).

It must be some sort of residual charge or current causin the driver of the speaker to run which eventually fades out as the residual charge runs out.

Never found a definitive cause though. V8 or else ...

Thanks fisha - That's a fascinating answer and one which I guess makes sense. Thanks for sharing that.

think mine does that all the time pal , least I don't need to ask now lol

Mine has just done this, scared the life out of me for a minute