It's possible that the hydraulic flow on your Thomas wheeled 153S may not be sufficient to actuate the sickle arm lift ram on your Wolverine sickle bar mower. The required hydraulic flow and pressure specifications for the mower should be mentioned in its user manual.
If the required hydraulic...
Here are a few troubleshooting steps you can try:
Check the connections: Make sure all the wires are securely connected to the servo and the switch. It's possible that a loose connection is preventing the servo from receiving the signal it needs to move.
Test the servo: Disconnect the wires...