No power to fuses

[Multicrazy]

No power to fuses

Hi all, I have a Golf 5 GTI Manual BWA engine 2008. I just wanted some guidance on how I can diagnose low voltage on fuses F6, F9, F10, F11, F12 (fuse box next to car battery) I am only getting 3.5v to these fuses and it’s throwing evap and fuel pressure regulator codes. I have tried giving those fuses direct from the battery and the codes go away. But how can I trace where these fuses get power from?

And also as a side note a few weeks back my ecu got fried and water got into it and the car wouldn’t start I had no check engine light. I’ve managed to get a donor ecu, with the cluster and keys as a set so the car starts good and even drives when giving direct power to those fuses. Could the Body Control Module have gone bad cause of the water and it might have short something in it as well? If someone can guide me where those fuses get power from that would be awesome!