The JLG aerial lift instrument cluster provides critical warnings tailored for telehandler and boom lift operations, helping operators navigate tight job sites and avoid tip-overs. Understanding these indicators is essential for preventing downtime and ensuring safety in construction and industrial environments.
JLG aerial lift Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | A critical fault has been detected on your JLG aerial lift, requiring immediate shutdown to prevent damage or injury. | Stop the lift safely, turn off the engine, and consult the JLG service manual. | |
| Master Caution | AMBER | A non-critical system abnormality is present; the JLG aerial lift can continue operation but should be inspected soon. | Check the secondary display for the specific fault code and schedule service. | |
| Check Engine (MIL) | AMBER | The JLG's engine electronic control unit has detected a fault affecting emissions or performance. | Have the engine diagnostics scanned by a qualified technician. | |
| Engine Oil Pressure | RED | Engine oil pressure is dangerously low, risking severe engine damage on your JLG aerial lift. | Shut down the engine immediately and check oil level and filter. | |
| Battery / Charging | RED | The JLG's charging system is not maintaining battery voltage, possibly due to alternator failure. | Inspect alternator belt and connections; have the charging system tested. | |
| Coolant Temperature | RED | Engine coolant is overheated, which can cause immediate engine failure on the JLG. | Stop the lift, let the engine cool, and check coolant level and radiator for blockages. | |
| Hydraulic System | AMBER | The JLG's hydraulic system has a fault, such as low fluid or filter blockage, affecting lift and drive functions. | Check hydraulic fluid level and inspect for leaks; see service manual. | |
| Low Fuel | AMBER | Fuel level is low on your JLG aerial lift, requiring refueling to avoid engine stalling. | Refuel with appropriate diesel or fuel type as specified. | |
| Glow Plug / Preheat | AMBER | The JLG's glow plugs are preheating the engine for cold start conditions. | Wait for the light to turn off before starting the engine. | |
| High Beam | BLUE | The high-beam headlights are activated on your JLG aerial lift for better visibility. | Use low beams when other operators or vehicles are nearby. | |
| Work Lights | GREEN | The work lights are on to illuminate the work area around the JLG lift. | Turn off when not needed to save battery. | |
| Beacon / Rotating Light | GREEN | The rotating beacon is active, warning personnel of the JLG's presence on the jobsite. | Ensure beacon is working for safety compliance. | |
| Swing / Slew Lock | AMBER | The JLG's turret swing lock is engaged, preventing rotation during transport or service. | Release swing lock before operating the lift. | |
| Overload / Capacity | RED | The JLG aerial lift's load has exceeded its rated capacity, risking tip-over. | Immediately reduce load or retract to a safe position. | |
| Fasten Seat Belt | RED | The seat belt is not fastened; the JLG requires operator seat belt use for machine operation. | Fasten seat belt before moving the lift. | |
| Parking Brake | AMBER | The parking brake is applied on the JLG aerial lift, preventing movement. | Release parking brake before driving. | |
| Brake Fluid Level | RED | Brake fluid level is low in the JLG's hydraulic brake system, causing reduced braking. | Check for leaks and top up brake fluid immediately. | |
| Air Filter | AMBER | The engine air filter on your JLG is clogged, reducing power and fuel economy. | Replace the air filter per maintenance schedule. | |
| Service / Hour Meter | GREEN | Displays total operating hours; when illuminated, scheduled maintenance is due on the JLG. | Perform the required service as indicated in the JLG manual. |
19 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Overload Warning
Common causes
- Exceeding rated load capacity
- Load shift during operation
- Improper load chart usage
What to do
Immediately reduce or reposition the load to within rated capacity. Retract the boom/arm to a safe position. Refer to the JLG load chart and operator manual.
Engine Overheat
Common causes
- Low coolant level
- Clogged radiator or debris buildup
- Failed cooling fan or thermostat
What to do
Stop the engine and let it cool. Check coolant level and inspect radiator for blockages. Clean debris and top off coolant; if recurring, consult a JLG technician.
Hydraulic System Failure
Common causes
- Low hydraulic fluid
- Contaminated or old hydraulic oil
- Blown hose or seal leak
What to do
Stop operation and check hydraulic fluid level. Inspect hoses and fittings for leaks. Add recommended hydraulic fluid and have the system serviced immediately.
Low Engine Oil Pressure
Common causes
- Low oil level
- Oil pump failure
- Clogged oil filter
What to do
Shut down engine immediately. Check oil level on dipstick; add oil if needed. If pressure remains low, tow the JLG to service for pump/filter inspection.
Battery/Charging System Fault
Common causes
- Battery terminals loose or corroded
- Alternator belt broken
- Faulty alternator
What to do
Inspect and clean battery connections. Check belt tension and condition. If light stays on, replace alternator or battery as per JLG specs.
Frequently Asked Questions
What does the flashing red master warning mean on my JLG aerial lift?
A flashing red master warning indicates a critical fault that requires immediate shutdown. Check the secondary display for a specific code and refer to your JLG service manual for troubleshooting.
How do I reset the service hour meter light on my JLG?
The service hour meter light is reset by following the maintenance reset procedure in your JLG operator manual. Typically, it involves pressing and holding a button on the instrument cluster with the key on.
Why is my JLG hydraulic system warning light on, but fluid level seems fine?
The hydraulic warning can also trigger from a clogged filter, high fluid temperature, or a sensor fault. Check the hydraulic filter and temperature; if okay, have a technician read the fault codes.
Can I operate the JLG lift with the amber caution light on?
Yes, you may continue operation with an amber caution light, but you should diagnose the issue soon. Ignoring it could lead to a red warning and component damage.
What should I do if the overload alarm sounds but I think the load is within limits?
Immediately stop and retract/boom down. Recalculate the load using the JLG load chart. If the load is correct, there may be a sensor fault; contact JLG service to recalibrate.
How often should I check the engine oil on my JLG telehandler?
Check engine oil daily before operation, or every 8-10 hours. Keep at the full mark and use the recommended oil grade in your JLG manual.