Reversing camera fixed but buzzing sound Fiat Ducato

[Budgie]

Hope some out there can help, I have had a problem with my reversing camera on our Autotrail Apache 634, if I turned on the ignition, the camera would work fine for about 1 min, but then the screen would flicker on and off turn black then turn blue, and would stay blue until the ignition was switched off and left off for about 5 mins, I could then turn the ignition on and it would repeat the same procedure
It make no difference if the engine is started or not. I have tried taking the uconnect fuse out to try and reset made no difference, so tried disconnecting the battery terminals and leaving disconnected for five mins so all the power drains away to hopefully reset the screen, hey presto the camera is fixed, after a few tests turns off ignition gets out the van well pleased with myself but then I hear a sort off electrical buzzing from the engine area, I really do not know if it has always been there and I have just noticed it or it has just started after I disconnected the battery. The buzzing noise starts when the ignition is turned on without firing the engine and stays on, when I turn the ignition off and remove key the buzzing lasts for 20 seconds then goes off.any help would be appreciated.