JLG 80HX-6 Boom Function Issues: Troubleshooting the Boom Up and Extend Functions

[MikePhua]

The JLG 80HX-6 is a popular telescopic boom lift used in various industrial and construction applications. However, some users have reported issues with the boom up and extend functions not working properly, while the down and retract functions are still operational. This issue can be caused by several factors, including hydraulic, electrical, or mechanical problems. Below is a detailed analysis and troubleshooting guide to help diagnose and resolve this issue.
Possible Causes for Boom Up and Extend Malfunctions

1. Hydraulic System Issues
   

The boom up and extend functions on the JLG 80HX-6 are powered by the hydraulic system. If there is a problem with the hydraulic fluid, pump, or valves, it can affect the performance of these functions while the down and retract functions may continue to work.

• Low Hydraulic Fluid: A low hydraulic fluid level can cause insufficient pressure to operate the boom up and extend functions.
  
• Solution: Check the hydraulic fluid level and top it up if necessary. Ensure there are no leaks in the system that could be causing fluid loss.
  

1. Hydraulic Valve Malfunctions
   

The hydraulic valve that controls the boom’s up and extend functions could be malfunctioning, preventing the boom from moving as required.

• Solution: Inspect the hydraulic valves for any signs of wear, damage, or blockages. If the valve is malfunctioning, it may need to be replaced or repaired.
  

1. Electrical or Control System Faults
   

In modern boom lifts like the JLG 80HX-6, the control of the hydraulic system is often electronically managed. Faults in the electrical or control system can prevent the boom up and extend functions from working, even if other functions like down and retract continue to operate.

• Solution: Inspect the electrical components, including the control switches and wiring. Look for loose connections, damaged wiring, or faulty relays. Check the fuses and reset the system if necessary. It may be helpful to use a diagnostic tool to check for error codes.
  

1. Joystick or Control Console Malfunctions
   

The joystick or control console that is used to operate the boom lift could be faulty, particularly the switches responsible for the boom up and extend movements.

• Solution: Inspect the joystick or control panel for any malfunctions. If the switches are worn out or damaged, replacing them may resolve the issue.
  

1. Pressure Relief Valve Issues
   

The pressure relief valve is designed to protect the hydraulic system by limiting pressure buildup. If this valve is stuck open or malfunctioning, it could result in a lack of hydraulic pressure, which may prevent the boom up and extend functions from working.

• Solution: Test the pressure relief valve to ensure it is functioning correctly. If the valve is stuck open or damaged, it may need to be repaired or replaced.
  

Step-by-Step Troubleshooting Guide

1. Check Hydraulic Fluid Levels:
   • Start by checking the hydraulic fluid level. If it is low, top it up with the correct fluid as specified in the operator’s manual.
     
   • Inspect the hydraulic system for any visible leaks or damage.
     
2. Inspect the Hydraulic Valves:
   • Inspect the boom control valves to ensure they are not blocked or malfunctioning. If necessary, test the valves for proper operation and replace any damaged components.
     
3. Test Electrical Components:
   • Check all electrical connections, fuses, and relays associated with the boom functions. Use a multimeter or diagnostic tool to check for electrical faults.
     
   • If a malfunctioning relay or fuse is found, replace them.
     
4. Inspect Joystick and Control Console:
   • Check the joystick or control panel for any issues. Look for worn-out switches or damaged wiring. Replace or repair any faulty components.
     
5. Verify Pressure Relief Valve:
   • Check the pressure relief valve for proper operation. If the valve is stuck open or damaged, it can cause hydraulic issues. Replace the valve if necessary.
     

When to Seek Professional Help
If after completing the above steps, the issue persists, it may be necessary to seek professional assistance. A qualified technician can perform more advanced diagnostics, including testing the hydraulic pump, solenoids, and control systems.

• Solution: Contact JLG’s service center or a certified technician to conduct a thorough inspection of the hydraulic and electrical systems. They will be able to identify more complex issues and provide repairs or component replacements as needed.
  

Conclusion
The JLG 80HX-6 boom up and extend function issues can typically be traced back to problems within the hydraulic system, electrical controls, or mechanical components. By carefully inspecting and troubleshooting common causes such as low hydraulic fluid, valve malfunctions, or electrical faults, most issues can be resolved without the need for extensive repairs.
Regular maintenance, including checking fluid levels, inspecting hydraulic components, and ensuring the electrical system is functioning correctly, can help prevent these problems from occurring in the future. If the issue persists after troubleshooting, professional assistance may be required to resolve the problem and restore full functionality to the equipment.