The reverse board, I'm not sure of the exact version but this should be valid for what the sockets are meant for.
Then this opic has a whole bunch of attached PDFs in replies https://ogrforum.ogaugerr.com/...everse-unit-question and specifically @Moonman posted these
Yellow and Purple are motor wires. Red and Black in the 4 pin plug are pickup and ground.
The 2 pin plug is power and ground for the sound board.