Bedford mw mechanical brake setup

[Jelleyboy]

Hi guys,

 

im finding my tail lights were constantly on when the battery was connected - the cav switch was off completely.

 

 

i couldn't get the brake lights on so I've tinkered and now have the brake and tail constantly on.

 

the isolation rotary switch does nothing to the brake lights and regardless of the brake switch being wired or not they remain on.

 

does this scream out as an earthing issue?

 

Any help greatly appreciated I have a few things to try from advice on Facebook but it's driving me mad