The JLG G5-18A instrument cluster monitors all critical systems on this telehandler, alerting the operator to safe operating conditions, warnings, and faults. Understanding these lights is essential for preventing damage and ensuring workplace safety. This guide provides model-specific meanings and actions for each indicator.
JLG G5-18A Warning Light Symbols
| Symbol | Name | Color | What it means | What to do |
|---|---|---|---|---|
| Master Warning (Stop) | RED | A critical engine or hydraulic fault has occurred on the G5-18A that demands immediate shutdown to avoid serious damage. | Stop the engine immediately and consult your G5-18A operator manual before restarting. | |
| AMBER | A non-critical system requires attention; the G5-18A can continue operation but should be serviced soon. | Check the other illuminated warning lights and schedule service for your G5-18A. | ||
| Check Engine (MIL) | AMBER | The engine control unit has detected a fault in the G5-18A's emission or performance systems. | Reduce load and have the engine diagnosed by a JLG dealer. | |
| Engine Oil Pressure | RED | Engine oil pressure is dangerously low in the G5-18A, risking engine seizure if continued. | Stop the engine immediately, check oil level, and top up if needed; if light stays on, do not run. | |
| Battery / Charging | RED | The G5-18A's alternator is not charging, or battery voltage is out of range. | Check battery terminals and alternator belt; if persists, have the charging system tested. | |
| Coolant Temperature | RED | Engine coolant temperature on the G5-18A has exceeded safe limits—potential overheating. | Stop the engine, let it cool, then check coolant level and fan operation. | |
| Transmission Temp | AMBER | The G5-18A's transmission fluid is above recommended operating temperature. | Reduce load and allow transmission to cool; if persistent, check fluid level and cooler. | |
| Brake System | RED | A fault in the G5-18A's service brake system has been detected. | Do not operate; have the brakes inspected immediately. | |
| Parking Brake | GREEN | The parking brake of the G5-18A is engaged. | Release the parking brake before moving the telehandler. | |
| Seat Belt | GREEN | The operator's seat belt is buckled on the G5-18A. | Ensure the seat belt stays fastened during operation. | |
| Glow Plug / Preheat | AMBER | The G5-18A's engine glow plugs are activated for cold starting. | Wait for the light to go out before cranking the engine. | |
| DPF / Regeneration | AMBER | The diesel particulate filter on the G5-18A requires regeneration to clear soot buildup. | Drive at moderate speed or initiate parked regeneration per operator manual. | |
| DEF / AdBlue | AMBER | DEF (Diesel Exhaust Fluid) level in the G5-18A is low or system fault detected. | Refill DEF immediately to avoid power reduction. | |
| Water in Fuel | AMBER | Water has accumulated in the G5-18A's fuel filter/water separator. | Drain the water separator or replace the filter. | |
| Low Fuel | AMBER | The G5-18A's fuel level is low and needs refueling soon. | Refill with diesel fuel to prevent running out. | |
| High Beam | BLUE | The G5-18A's high beam headlights are on. | Switch to low beam when approaching other vehicles. | |
| Hydraulic System | AMBER | The G5-18A's hydraulic system has a warning condition, such as low fluid or high temperature. | Check hydraulic fluid level and temperature; reduce load if necessary. | |
| Fasten Seat Belt | RED | The operator's seat belt on the G5-18A is not fastened. | Fasten seat belt immediately before operating. | |
| Engine Oil Temperature | AMBER | Engine oil temperature in the G5-18A is approaching maximum safe limit. | Reduce engine load and allow oil to cool; check oil level. | |
| Air Filter | AMBER | The engine air filter on the G5-18A is restricted and needs servicing. | Replace the air filter element. | |
| Fuel Filter / Water Separator | AMBER | The fuel filter/water separator on the G5-18A requires replacement or draining. | Replace fuel filter and drain water separator. | |
| Service / Hour Meter | AMBER | The G5-18A has reached a scheduled maintenance interval based on engine hours. | Perform the required service as per the operator manual. | |
| Work Lights | GREEN | The G5-18A's work lights are turned on. | Turn off when not needed to save battery. | |
| Beacon / Rotating Light | GREEN | The warning beacon on the G5-18A is active. | Ensure beacon is on when operating near pedestrians. | |
| Swing / Slew Lock | AMBER | The swing lock on the G5-18A is engaged to prevent rotation. | Disengage swing lock before driving on slopes or rough terrain. | |
| Differential Lock | GREEN | The differential lock on the G5-18A is engaged for maximum traction. | Disengage on hard surfaces to prevent driveline damage. | |
| PTO Engaged | GREEN | The power take-off (PTO) on the G5-18A is active, driving auxiliary equipment. | Ensure PTO is disengaged before road travel. | |
| Overload / Capacity | RED | The G5-18A has exceeded its rated load capacity and is at risk of tipping. | Reduce load immediately to a safe level. | |
| Low Oil Level | AMBER | Engine oil level on the G5-18A is low and needs topping up. | Check engine oil and add oil to the correct level. | |
| Brake Fluid Level | RED | Brake fluid level in the G5-18A is low, affecting brake performance. | Check brake fluid reservoir and top up; inspect for leaks. | |
| Door Open | AMBER | The cab door on the G5-18A is not fully closed. | Close and latch the door before operating. | |
| High Exhaust Temp (HEST) | AMBER | Exhaust temperatures on the G5-18A are elevated during DPF regeneration. | Avoid parking over dry grass or combustibles. |
32 symbols shown. Icons follow ISO 2575 dashboard standards; exact graphics vary by model year.
Most Important Warning Lights
Master Warning Light Stays On
Common causes
- Critical engine fault
- Hydraulic system failure
- Low oil pressure with engine running
What to do
Stop the G5-18A immediately. Turn off the engine and consult your operator manual. Do not restart until the cause is resolved by a qualified technician.
Engine Overheating (Coolant Temp Red)
Common causes
- Low coolant level
- Radiator or fan blockage
- Coolant pump failure
What to do
Park the G5-18A safely, run the engine at idle for a few minutes, then shut it off. Wait for cooling, then check coolant level and clean the radiator fins. If recurring, have the system inspected at a JLG dealer.
Hydraulic System Warning (Amber)
Common causes
- Low hydraulic fluid level
- Hydraulic oil over temperature
- Contaminated fluid
What to do
Check the hydraulic tank level and top up with recommended fluid. If the light remains, reduce load and allow the system to cool. Persistent warnings require dealer service.
Overload Light Engaged
Common causes
- Exceeding rated load capacity
- Load shift during operation
- Incorrect attachment
What to do
Immediately lower the load and move to a safe area. Remove excess weight or rebalance. Refer to the G5-18A load chart before lifting again.
DEF/AdBlue System Warning
Common causes
- DEF fluid level low
- DEF quality or contamination
- DEF injector or pump fault
What to do
Refill DEF with approved fluid. If the light persists, the system may need regeneration or servicing to prevent power derating.
Frequently Asked Questions
What should I do if the Master Warning (red) light comes on while operating the G5-18A?
Immediately stop the engine and assess the situation. Check other warning lights. Do not restart until the fault is resolved; contact your JLG dealer if needed.
Can I continue driving if the DPF Regeneration light is on?
Yes, drive the G5-18A at moderate speed (above 5 mph) to allow passive regeneration. If the light blinks, park and initiate stationary regeneration per the manual.
How do I reset the service hour meter light on my G5-18A?
The service light must be reset by a JLG dealer after performing the required maintenance. It cannot be reset by the operator.
Why is my engine oil pressure light on even after topping off oil?
This could indicate a faulty oil pressure sensor, a clogged oil filter, or internal engine wear. Have the G5-18A inspected by a mechanic; do not operate without oil pressure.
What does the hydraulic system warning mean for my G5-18A?
It typically indicates low fluid level, high temperature, or a filter restriction. Check the hydraulic tank, allow cooling, and if persistent, consult a technician.
Is it safe to operate with the engine air filter light on?
No, a restricted air filter reduces engine power and can damage the engine. Replace the filter before further operation.