I'm interested in rewiring my Telecaster 3-way switch to series vice parallel wiring (will not use 4-way switch). Looking at a SD 4-Way Switch schematic there is an IMPORTANT note explaining "the neck pickup's cover must be ground with a separate wire (you will need to disconnect it from the black wire first). I don't understand this at all. Are there any resources, either photos or other schematics that explains this further? I'm confused by the SD schematic as it only shows one black wire from the neck pickup to the swith but no "disconnected" wire or any wirefrom the cover (and where do you connect that to)? Thanks.