Center J/B
Install the four 3A (from Cowl Wire) connectors on the one side, and install the four 3B (from Instrument Panel Wire) connectors on the opposite side.
It dose not matter at which position each 3A or 3B connector is installed provided that the same type of connector are all on the same side.
Provided that all the same terminal codes are lined up in the inner circuit as shown above, they are connected within the Center J/B.