I got myself an EMG 89, I think it's pretty similar to an 85 only it's splittable.
I know it's an active humbucker. The coil tap on mine is operated by pulling out or pushing in an ordinary looking tone knob. I use a little two way switch to turn the pickup on and off

I RECOMMEND SUCH A FEATURE TO ANYONE MODIFIYING THEIR GUITAR, I'M CHUFFED WITH IT.

If I set the pick up selector exclusively to that pick up the on off switch can completely kill the sound producing this cool stuttering effect. If the pick up selector is selected so that my EMG 89 and my middle pick up are selected the kill switch makes a nice kind of tone and volume fluctuation, harsher and louder on the one hand, warmer and quieter on the other. This latter effect is more manageable I find, I particularly like it with out of phase unison bends that wail and burn.
Some of Rage Against the Machine's Tommy Morello's sounds come from using an on/off switch.