yamaha pickup wiring diagram

Just wondering if anyone here knows anything about yamaha pickups. My old bass (pearl rip-off of a fender jazz) hummed way to much, and eventually i got Yamaha 5 string P and J pickups to replace the old unshielded paperweights.
Problem is, i can't seem to get them to work. The old ones were simple 2 wire PUs, the new ones have common shielded red&white wires, and a blue, giving 4 wires. the shield is connected only to the PU case shield, and i've measured 100kohm red-white, 300kohm blue-white, and 400kohm blue-red (all at DC).
I've tried just about every combination of wiring, differential pre-amps, using one as a centre tap of the other 2, contacting yamaha (thanks for the reply, 2 months and nothing...). I can't think of much else, i know the pickups work, just not in my bass...
I'm a 4th year elec eng student, i've built myself amps, speakers, effects, etc (in short, i'm not an idiot), but this escapes me.
any help will be greatly appreciated
richard

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