Unknown buzzer sound. Potential causes?

Have you got a Bee or a Wasp trapped in your cab  ?.

Have you got some sort of electrical fault? ‘Bing bong’ is usually associated with doors or belts and ‘buzzer’ lights. 

Alarm Clock perchance  

Don't dismiss insect activity! Several years ago I could hear a 'sound'  from our kitchen, I thought it was the first drops of rain hitting the then conservatory glass roof..I can't tell you the times I shot out to grab the washing before the downpour.  It was never raining!

Eventually I watched an insect enter one of the wooden roof struts. We knew the conservatory needed replacing it was from the 1930's and we couldn't afford to replace when we bought the house, so tidied it up.

Turned out it was a leaf cutter bee who found the soft wood wonderful for its brood.

It took weeks to discover and then we had to wait for the bees to emerged before we replaced the conservatory. 

Once on site in Devizes we watched a blackbird  going under a motorhome with nesting material. We told the owner and when they looked there was an almost complete nest in the engine compartment. Sadly I expect all the effort on nest building was wasted even though the nest was carefully sited in an adjacent hedge 😪