Riddle me this…pickup question

[JGale]

So…I placed a P90 in the bridge of a 4 knob Godin with a Lollar Imperial neck and now the overall volume is acting funky around full vol to about 8.  
Turn both to 10 and back off either and it gets much louder. 
4 conductor neck, 3 wires on the P90 ( although the accompanying neck P90 has 2 ). 
Wat up?

[JGravelin]

P90 is OOP with the neck hb. For any single coil and hb to play nice together, the single must be wound in the same direction and have the same magnetic polarity facing the stings as the hb coil that is grounded (screw coil, south up.).

I would first check the string-facing magnetic field of the P90. It's it's S up, then you're in good shape. If not, flip the magnets. Then, since you mentioned your P90 having 3-cond output leads: I'm assuming one of those is the true ground, the other 2 are coil "start" and coil "finish". Try swapping the start and finish and see if that does the trick.

The solution will lie in one or the other or both together.

Finally, check both the bridge and neck vol pots and make sure that your soldered hots aren't accidentally touching the middle lug.

[JGale]

ANSWERED!

Thank ewe!

[veatch]

.... or leave it out of phase so you can play groovy tunes like this