I had a hum and signal cutting out issue with a pickup ground lead being nearly shorted near the switch lug. It was baffling, but I just grabbed the wire with both thumbs/index fingers and manipulated it at different points until I found the short.
Hi Scott. Thanks for illuminating. Not to be argumentative, but it's actually possible that ungrounded shielding in the pickup cavity can cause noise -- especially with a stacked type design. From my experience and research, I don't think there is any real value in shielding the pickup cavities, while twisting lead pairs, and shielding the control cavity is beneficial. Aluminum shielding under the pick-guard, bridge plate, and/or pickup, but not wrapped around the pickup can reduce rheostat generated noise.
Does learning to make the best of what you have require learning how it functions?