Bad wiring on UV

[JN777]

i just installed a seymour duncan jb in the bridge position on my Universe. my problem is that in the forth position (single/bridge) the volume decreases like a 90%. what did i missed?

Thanks in advance for your help.

[steve]

You'll probably have to reverse the phase of the SD-JB - swap the hot and ground around.
Then you might find that the wrong coil comes on for what you want when the bridge is split/combined with the middle single... In which case, you'd have to physically flip the bridge pickup around...