I recently bought an old electric guitar (an SG copy) on eBay, as a little restoration project. I have some basic experience with electronics from university, but that was 15 years ago and I've never worked on a guitar before.
There's no sound from the neck pickup. I got out my soldering iron and multimeter and checked each component individually - the switch, all four pots and both pickups look to be working fine. While doing that I noticed something strange about the wiring, and I think there's a ground connection missing.
The existing wiring mostly matches the wiring in the diagram shown below, just with the bridge and neck pickups swapped. The ground from the bridge is soldered to the bridge volume pot, which has a wire connecting it to the bridge tone pot, which is further connected to the neck tone pot, grounding each of those three pots. But unlike the diagram, that's where it ends - i.e. rather a ground connection joining all four pots as in the diagram, the neck volume pot (in the position of the bridge volume pot on the diagram) seems to be ungrounded. (found on sixstringsupplies.co.uk).
Am I correct in thinking this would explain the lack of sound from the neck pickup?
If I add this final ground connection, is there anything special that I need to keep in mind with the choice of wire? Or can I use basically anything that can be soldered and conduct electricity?