Wiring help. Am I missing a wire or what?

IIRC, for a Seymour Duncan MM pickup, the red and black go together for the hot, and the green and bare go to ground.

 

Try to locate a wiring schematic for the pickup. That may tell you which is which. If you only have three wires they most likely are a hot from each coil and a ground. If possible, check the pickup where the wires attach and see if you locate which goes to the baseplate. That's the ground. Sorry I can't be more precise, but I'm not familiar with the hardware in question. Hope this helps.

 

According to the Seymour Duncan site, Slater is correct in post #2. Best to you both.

 

That works for parallel operation, but if you want it in series...

If you have a multimeter, measure the resistance (Ohms) between each lead:
red - green
red - black
green - black

let us know the results

 

I’m not positive, but I think you need a different model SD MM pickup with a fourth, white wire to do series/parallel.

 

I'm just guessing, but I think black to hot & green to ground would put it in series (leaving the red disconnected).

 

If you have hum, maybe one of the coils isn't functioning, which would be a byproduct of wiring it up incorrectly.
If that red wire is the center wire (between the two coils), having it connected is shorting one of the coils.

Do you own a multimeter?

 

Another way you can check if one coil is shorted is turn up the gain on your amp & then tap the pole pieces of the pickup with a screwdriver tip.
If one side is much quieter than the other, that's a shorted coil.

 

There should also be a ground wire from the bridge that should now be connected to the ground lug of the output jack for direct to jack wiring.

 

You're getting more highs & more output w/o controls.

The noisy power would have been counteracted if it was operating in humbucking mode, so I still think you might be operating on only one coil.