I know these DiMarzios were bought used, not saying they are faulty but - try some other pick ups & see, If that fails you could ask DiMarzio for advice.
The wiring on the control plate you have is correct & compares to the circuits shown for Jazz bass by many manufacturers, typically DiMarzio, Seymour Duncan & Fender, using Audio Log taper CTS Premium pots. The connector blocks are a straightforward & simple way to connect the pick up wires without soldering.
I have already offered to look at the bass, but do try some other pick ups first.