Brake circuit issues?

Hi guys

Having a bit of trouble with my Gen1 SV650S 1999 model

Everytime the brake switches operate it either dims the other lights (I.e. headlights and dashboard lights such as neutral and High beam indicator) or kills the main 30A fuse


Now I've checked the wiring for continuity and resistance and all seems clear. Disconnected the tail light unit and the problem was still there.

It happens with both front and rear brakes. I can only imagine that its a bad ground somewhere but surely it would show on the continuity meter?

Could anybody shed some light on this?

Is this with one or both brake switches? That'll isolate which part of the circuit it is thats causing the issue.

Its both switches. I disconnected one to try isolate it but it was still happening on either switch

[Sid Squid]

Reconnect the rear light, remove both bulbs, disconnect both switches at the loom. At either switch connector on the main loom use a jumper between the wires, same problem? If yes the fault is that the white/black wire is damaged somewhere in the loom.
if no then the fault lies in either of the switches - I'd check the wiring of the rear switch and the short section from the loom connector to to the front switch first.