Should be an individual eddy board under the playfield, near the right outlane.

Check to see if the led is lit and if so adjust the pot on the board until the led just goes out.
Then try running  a ball over the top of the switch to see if the led lights when the ball is sensed.

If your led is out to start with and not responding to ball passes, you can adjust the pot until the led lights, then back it off slightly until it goes out again.

Also try reseating the connector to this eddy board.