Hey folks,
I'm about to finally finish my July guitar (lol), but I think I got a bad solder joint.

It was working for a brief moment yesterday, then I heard a crackling noise and after that... it stopped working.
That means that the NECK pickup is still working as intended, with the switch in the neck position. NO sound at all in the middle or bridge position.

I have already resoldered the whole thing yesterday, changing every pot and most cables. I have no replacement switch so I kept it for now, but I need help how to find the problem.

The pots are all at half position, so nothing is rolled off and I should hear something.

I have a multimeter. How do I proceed now? I don't want to to upload a photo and ask you to find the error for me, I'd really love to get some hints how to diagnose and fix the problem myself.

The wiring diagram I was following: https://www.pitbullguitars.com/wp-co...m4Pot%20v5.pdf

Where and how would I now best start to search for the error? What would cause the neck pickup to work fine in its own position, but not in the middle? Does the bridge pickup have a short somewhere that causes the neck pickup to be shorted out, too, in the center position, or does it relate to the switch?

I appreciate your help, thank you =)