There are some problems with your diagram, but rather than fixing them outright, I/we need to know something first - do you want S2 to produce series only when S3 is in the middle position, or do you want a series connection no matter what position of S3 is selected?
Because the two methods are wired a bit differently, I'm asking you which way do you want it?
Do it this way to bypass the 3-way switch when in series. When pulled up, one pole of the P/P connects bridge black to neck green to form the series connection. The other pole connects neck black to output and disconnects the yellow wire from the 3-way. The blue wire shown on your digram remains connected to the common lug of the 3-way; the other end meets the neck black at the P/P lower right lug.
In Reply #3, frets did specify that she'd like for B or N to be available when the push-pull as been pulled up for series. Your diagram will make the series connection in all three positions. But it's certainly a quick way to achieve the goal if that the user wants.
Try this: I've included both a schematic and a layout (simplistic, I know), but the deal is, I've written it to be a generic module that can be dropped in almost anywhere that the user wants what you want - series or parallel in the Middle position only.
Note that I've excluded the coil-split wires and switching, you've already got that part drawn correctly, no need for me to duplicate it. The sad part here is, you'll be rewiring your pup selector from the ground up, no easy "move a wire and you're done" for you. Sorry!
The layout diagram first:
And then the schematic. I include this merely for review by others who may stumble across this thread, sometime in the future.
Sadly, this does have have the Hanging Hot issue, as do nearly all simplistic versions of a series connection. To overcome that requires a more complex scheme, and for what it's worth, 99% of the players out there don't find this version objectionable.... unless they're in a very noisy environment.
Last item: why did I wire the ser-par switch like that?
First, your brain is still working like it should, the latest diagram (just above) will work as newey instructed you to hook it all up. Just be aware that this will give you the series (B * N) in all three pup selector positions.
EDIT: Oops, I missed it the first time around. Your description of S2 does not reflect reality. It should state that S2-up gives B * N in all three positions, not just in the Middle. That's true for the diagram shown, and you should leave it (with the updated description) for others to view. If you want the series connection in Mid only, I respectfully suggest that you rest up a bit, then tackle my modifications. At that point, you can change the S2 description back to what it currently states, and post that new version for all to see and applaud!
Second..... Geez, Louise, you just can't catch a break, can you? That hurts just to hear you mention it. I feel for ya, and I'm praying that you come out on the other end with all brain cells intact and firing as desired.
Your schematic and diagram are correct. But it's a bit confusing, since the wiring in the diagram doesn't exactly match the schematic. They are electrically equivalent, but not exactly the same.
Aren't you the one who parrots me on occasion, stating that the schematic is divorced from any physical necessities? (Or words to that effect.)
Excepting the ground connections, I chose to show one way the wires could be hooked up. When it comes to the actual internal cavity, different routing may suggest itself to the modder. At that point, a layout diagram is only a good starting point, or as a guide if you will, and should never be taken as the only way everything can possible be hooked together.
Also, I did intend, and suggested, that frets could simply drop this into her diagram as an overlay view. I don't particularly wish to ingest someone's diagram into a graphics program and massage it as if I were the original creator, that's a skill set that I don't have, and don't foresee myself acquiring in the future - near or long term. But if a member here, like say for instance frets, were to ask me, I'd probably do my best, and let the chips fall where they may.
I’m saving both designs for future use. Here is the final of the Series in all positions updated according to Sumgai’s editing of the fact that pulling up on SW2 puts the B*N into Series in all 3 positions.