To me, the soldering work looks very neat. The only thing I don't like is that cap.
The legs of that cap aren't isolated.
When closing the tap, you can accidentally move that cap and shortcut some hot lug near.
Additionally, if some leg is in the hot path, and that leg touches the cavity, you are also shorting there.
Independently of if this is your current issue or not, I suggest you to isolate those legs, with electrical tape or with some heatshink tube (neatest).
Check this kind of potential shorts. I usually try to isolate every hot lug, to avoid any accidental shortcut.
I had experience with guitars that worked fine just until the moment that I closed the tap. When mounting the tap, I had to push some wires inside and, some accidentally shortcutted some parts of the wiring.
Just my 2 cts.
Can you please attach some pictures of the rest of the wiring?
Better than this, can you please attach some sketch where you show how every wire is actually connected?
I miss something there, the link between volume and tone pots, also, I don't see very clear how did you wired the killing switch. Usually, kill switches have connected the jack's hot and ground, as well as the hot output of the circuit, but It seems to me as if it was linked to the tone pot, instead to the pickup's selector.
A diagram, even hand-made would be very helpful to catch the bug.