Hi.

I'd look at the output jack first. You've screened the inside of the jack socket hole, and this is a classic place for the signal to get grounded. You should be able to move the jack plate away from the body with a jack still in it, so if you get your signal back, then you know that's the cause. If you've got any insulation tape, then try and stick it over the copper tape in the hole.

Otherwise look for any stray strands of wire touching the copper screening. It only takes a single strand to ground all the output.

But if all the output is lost regardless of switch position, then the signal must be grounded between the switch output and the jack socket, which makes the jack socket tip prong touching the shielding the most likely suspect.