I just installed a brand new set of Stew-Mac "Golden Age" humbuckers in my Sheraton. The neck sounds great! The bridge sounds very thin and relatively weak. Since they're 4-conductor pickups, and since other pickups in the same guitar have been fine, my theory is that the bridge pickup is only using one coil. However, the red/white leads come soldered together from the factory, and I've checked the integrity of that connection. I'm assuming maybe there's a lead loose inside the pickup, maybe. I know I could measure the resistance at the hot and ground leads with the pickup out of the guitar. Is there any way to make the same measurement without taking it apart? Maybe at the jack? The electronics are LP/335 style, vintage wiring.