Fault Phenomenon: John Deere 850K dozer instrument displays blade angle data jumping or lost, automatic grade control fails.

Troubleshooting Process:
– Checked harness: sensor harness worn at blade swing point.
– Checked signal: signal intermittent when harness moved.
– Checked connector: connector pins oxidized.
– Checked sensor: sensor body normal.

Root Cause: Frequent blade swing movement caused the sensor harness to wear at the fixation point, causing the signal wire to intermittently short to ground or open circuit.

Required Parts: Repair or replace blade angle sensor harness, add protective sleeve.