Mk6 t350 side no side lights

[Mk6125ps]

Can anyone help,my mk6 t350 side lights have stopped working no front back or cab marker lights Iv checked the fuses and tested the fuse box in the dash but there isn’t power to some of the fuse holders including the side lights so I jumped power from one that has 12v and still no lights working I’m waiting for a relay tester to come in the post but any help would be appreciated is there a common fault I can check ie wires for damage any idea why Iv lost power to some but not all the of the fuse box? Thanks