Why would a Jazz Bass pickup show normal DC resistance and have extremely low output? The other pickup is fine, the wiring is fine, but this pickup has almost no sound. I connected both pickups directly to the output jack (one at a time) to eliminate the wiring in the bass, and one pickup sounds fine and the other has almost no output. I tried reversing the polarity, no difference. The pickup isn't shorted and it's not open. What gives? Well, I just checked the magnetism with a screwdriver - the low output pickup has no attraction and the good one has strong attraction. I guess that's the problem. Are pickups magnetized after they're wound? Or are the magnets already there?