This wiring diagram is taken from my 1982 (Version 1) Thunder II active bass. It should also be suitable for the version 2 Thunder II active bass, and the Thunder III - as far as I know the only difference between the circuits for these guitars is that the later models have a different pickup in the bridge position.
The volume and passive tone pots are 500K log/audio, the active tone pot is 500K with a centre detent. The tone capacitor is 0.022 microfarad Mylar.
The active on/off and phase switches are DPDT mini toggle switches, the dual tone switch is a 4 pole changeover mini toggle.
The original switches have an earth wire soldered to the metal parts of the switch body - this is not necessary and if you are replacing the switches with modern ones (Which usually have plastic bodies) is not advisable - connect the earth wire directly to the back of the active tone pot and not to the switch bodies as shown below: