Buzz noise from rear

[Sweety]

Hi guys

have an issue with flat battery if car left for more than 2 days.
Traced it back to a constant buzz and tick noise from rear by fuel tank
Must be what’s draining the battery as battery passes all test and isn’t showing any faults, also fitted Bluetooth battery tester that shows alternator Charing battery fine.
so back to the noise which I noticed this evening, electronic noise, constant when car switched off locked…..
Tried…
Disconnection battery from 10 mins
Has anyone else had this issue. 2016 B6 I feel it must be from the fuel pump or something around that area.

 

[Sweety]

Hi guys

have an issue with flat battery if car left for more than 2 days.
Traced it back to a constant buzz and tick noise from rear by fuel tank
Must be what’s draining the battery as battery passes all test and isn’t showing any faults, also fitted Bluetooth battery tester that shows alternator Charing battery fine.
so back to the noise which I noticed this evening, electronic noise, constant when car switched off locked…..
Tried…
Disconnection battery from 10 mins
Has anyone else had this issue. 2016 B6 I feel it must be from the fuel pump or something around that area.

Forgot to say the noise is there all the one it’s a electronic sound of a tick and buzz it’s Pulses every 5/10 seconds