Power for the flippers is not separated left and right. All flippers share the same power circuit and start on the top playfield then to the lower.
Check for power at the non-working flipper coil and report back.
Carefully inspect all the solder joints on the non-working coil looking for broken wires to power, ground and EOS.
Carefully inspect the EOS switch for proper function. With the game on, press the flipper button and manually lift the flipper and see if it stays up.
Carefully inspect the cabinet flipper leaf switch to make sure it is making solid contact and solid solder joints.
There are 2 connectors in the path that can cause problems with the ground side of the circuit. From the flipper button, the ground signal moves through the cabinet wiring, to a connector to the PF, then though the connector between the upper and lower playfields. Check the lower flipper ground wire on both these connectors.