Buzzing Noise from Boot

[Todge90]

Hi my 09 Multispace 1.6Hdi has just developed a strange buzz from the rear near side some where behind the panel in the boot.

Only way to stop it seem to be to disconnect the battery!
Any ideas?

Thanks in advance

UPDATE:- The act of removing the panel silenced the buzzer!  Right old rats nest of wiring in there. I was shocked to see it.

[Oi69]

Hi do you have a towbar fitted ? as it might be the relay or buzzer on the board that is normally fixed to run the electrics as thats where they put it