JLG 600S Intermittent Ground Fault Alarm When Boom Elevated
Fault Codes & Symptoms
Intermittent ground fault alarm Related symptoms: - Erratic function of platform controls - Loss of power to platform outlets The ground fault alarm goes off, but only sometimes. It seems to happen when we are up in the air and swinging the boom.
Confirmed cause: Internal break in the primary ground conductor inside the main boom harness, approximately halfway up the boom. Repair performed: Replaced the entire main boom harness assembly. Splicing was not recommended due to the dynamic application and the need for long-term reliability. Ensured all harness clamps were properly installed and not over-tightened. Verification: Elevated the boom to full height and swung lock-to-lock multiple times. Operated all platform functions through several cycles. The ground fault alarm did not reoccur. Technician notes: - The internal wire break had no external signs of damage. The insulation was intact. - This type of failure is common on high-hour machines where the harness is subject to constant flexing and environmental exposure. - Carefully check harness routing and clamping during installation to prevent repeat failures.