I haven't seen a stock pickup with that color leads, but from what you've said, I've edited your picture to show a correction.
If YOU say red is the ground/shield for the cover, it should go to ground on the back of the volume pot. It LOOKS like you may have tied it to the wrong end of the jumper you cut. It should be soldered to the tab of the cover, not the eyelet for the coil's ground lead (you say white).
You say the white is the old ground lead, so it should go to the 4-way. The 4-way mod works by switching the neck pup's ground lead, not its hot lead.
YOU say the blue is the hot, so it should go straight to the volume pot's input lug.