If you have a bulb operating on 25v with a resistor, make sure it is a 44, not a 47. It won’t cause any real issues, but the 47 is less of a load, therefore the voltage will be higher-around 12v instead of 6v. It will burn bright and fail prematurely.

The ball return switch is around 12-E on the schematic, right by the (O) ball return relay.

There’s a number of switches in line with the ball return coil and relay, could be any one of those.