MM switch wiring - puzzled

[tauzero]

My Squier Vintage Modified Modified was modified by replacing the bridge pickup with an MM pickup, which has a 3-way toggle switch for switching series, parallel, and single coil. I wasn't entirely clear on how this was accomplished with a DPDT switch, so went in search of wiring diagrams, and that just puzzled me some more. 4-wire MM pickups are all going to be similar so I found a wiring diagram for a Nordstrand MM4.

 

 

The switches are DPDT on-on-on ones (this is specified in a PDF on Nordstrand's website).

 

Series and parallel are easily worked out. 

 

Parallel (the bottom contacts are made):

• ground-green-white
• live-black-red

 

Series (the top contacts are made):

• red-white
• green-ground
• black-live

 

But how does single coil work? On-on-on toggles connect both throws to their individual poles AIUI (unless I'm mistaken in my belief) so the resulting connections on the bridge pickup are

• ground-green-white
• live-black-red-white-green-ground

because of that diagonal connection of the white lead. So that seems to short out both coils. I must be missing something because it works on the Squier, which is wired up to that pattern (albeit with the colours in a different order but still with a red-green coil and a black-white coil). Can anyone enlighten me?

[Acebassmusic]

It took me a while to get my head around this when I was first trying to install series / single / parallel switches in one of my basses. I then came upon this diagram showing 2 types of DPDT switch connections. It looks like the one in your diagram is type 1.

 

 

Using this diagram and inserting the switch connections (in red) onto your diagram lets you see the current flowpath.

 

Parallel

 

 

Series

 

 

Single

This one is different because (for the top pickup) the current flows from the + , throught the black wire / pickup / white wire to the switch and then on to ground. Although the green wire is connected to the switch terminal the flow gets dead ended throught theother pickup to the red wire. Hope this helps

 

[tauzero]

Thanks, yes, it was only the middle position that was puzzling me. I've ordered an on-on-on switch, must check it and see which type it is before using it.