Help with electrical woes..

The turn signal switch is not "grounded" All functions through the TS switch are a series switched function, in a "hot" lead.

As above^^start by checking the rear sockets and grounds.

You can also isolate this

A....is it in the front, in the TS switch?

B....or is it further back?

by disconnecting the rear harness at the kick panel connector. This will leave the brake switch power going into the TS switch. If it doesn't blow a fuse, it's "back there" somewhere

I would also pull the rear seat out and inspect where the rear harness goes through the area of the bottom corner of the seat, look for bare, aprasion, etc.