Fault Phenomenon: Palazzani telescopic handler cannot switch between crab steer and front steer modes.

Troubleshooting Process:
– Checked steering mode selector switch: switch damaged.
– Checked steering cylinder position sensors: sensor signal error.
– Checked hydraulic directional valve: spool stuck.
– Replaced selector switch and position sensors.

Root Cause: The steering mode selector switch and feedback sensors failed.

Required Parts: Selector switch, angle sensors.