Restoring Drive Functionality on the JLG 2646E2 Scissor Lift

[MikePhua]

The JLG 2646E2 and Its Place in Aerial Work Platforms
The JLG 2646E2 is a battery-powered electric scissor lift designed for indoor and slab-surface applications. With a platform height of 26 feet and a working height of 32 feet, it offers a compact footprint and quiet operation ideal for warehouses, maintenance tasks, and construction finishing work. Manufactured by JLG Industries, a company founded in 1969 and now a global leader in aerial access equipment, the 2646E2 was part of a generation of lifts that emphasized safety, simplicity, and low emissions.
JLG’s electric scissor lifts have been widely adopted across North America and Europe, with thousands of units in circulation. The 2646E2 features proportional controls, onboard diagnostics, and a drive system powered by DC motors and hydraulic actuators. Despite its reliability, age and intermittent use can lead to electrical and hydraulic issues that require careful troubleshooting.
Terminology Annotation

• Tow Valve: A manual hydraulic valve that allows the lift to be moved without power by bypassing the drive system.
  
• Main Relief Valve: A pressure-regulating valve that limits maximum hydraulic pressure to protect components.
  
• Drive Solenoid: An electrically activated valve that controls hydraulic flow to the drive motors.
  
• Membrane Pad: A sealed control interface with buttons for drive, lift, and traction functions.
  

Initial Symptoms and Diagnostic Path
The lift in question exhibited weak drive performance, stalling on minor surface irregularities and failing to move on gravel. While lift and steering functions were responsive, drive power was inconsistent. This pointed to a hydraulic or electrical fault in the drive circuit.
The first step was to inspect the tow valve, which was confirmed to be fully closed. Next, a pressure gauge was connected to the MP test port on the valve manifold. With the drive solenoids disconnected and the joystick activated, the system only produced 1,700 psi—well below the expected 3,000 psi. This suggested a pressure loss or electrical fault preventing full activation of the drive system.
Electrical Fault and Relay Repair
Upon inspecting the control board, a bent pin was discovered on one of the small relays. After carefully straightening the pin and reinstalling the relay, the drive pressure immediately returned to 3,000 psi. The lift regained full drive functionality, confirming that a minor electrical fault had disrupted the hydraulic control signal.
This highlights the importance of inspecting connectors, relays, and pins for physical damage. Even a single bent contact can prevent solenoids from energizing, leading to misleading hydraulic symptoms.
Drive Behavior and Traction Limitations
The JLG 2646E2 is classified as a slab machine, meaning it is designed for flat, level surfaces. While it can handle slight grades, it is not intended for uneven terrain or gravel. When one wheel loses traction, the other may not compensate due to the open hydraulic circuit design. This is normal behavior for standard drive controls.
For machines with proportional controls, a “Traction” button on the membrane pad can be used to temporarily boost drive torque. Pressing and holding this button while one wheel spins may allow the lift to overcome minor obstacles. For standard controls, engaging “Hi Drive” can achieve a similar effect.
Control System and Limit Switches
Years later, the lift failed to drive again despite functioning lift and steering systems. The joystick’s trigger and enable LEDs illuminated correctly, and limit switches on the battery and pump hatches were audible. However, no drive response occurred.
Further inspection revealed that pressing the joystick did not activate the drive solenoids. This pointed to a possible controller fault or broken signal path. The technician, equipped only with a Swiss army knife, verified that the trigger and enable switches worked, but the joystick’s directional output was absent.
This scenario underscores the importance of having proper diagnostic tools and understanding the control logic. A faulty joystick, damaged wiring, or failed controller can all prevent drive activation even when other systems appear functional.
Preventive Maintenance and Long-Term Storage
The lift had been stored and maintained for years, with batteries kept charged and components periodically tested. This level of care is commendable, but intermittent use can still lead to corrosion, relay fatigue, and connector degradation.
Recommended practices include:

• Cycling all functions monthly to prevent contact oxidation
  
• Replacing relays every 5–7 years regardless of use
  
• Cleaning and reseating connectors annually
  
• Using dielectric grease on exposed terminals
  
• Logging fault codes and pressure readings during each inspection
  

In 2023, a facility manager in Ontario implemented a quarterly lift activation protocol for all stored aerial platforms. This reduced startup failures by 80% and extended battery life across the fleet.
Conclusion
The JLG 2646E2 is a reliable and capable scissor lift when maintained properly. Drive issues often stem from minor electrical faults, such as bent relay pins or degraded connectors, rather than major hydraulic failures. Understanding the interplay between control signals, solenoids, and pressure regulation is key to restoring functionality. With regular testing and preventive care, even older lifts can remain dependable tools for elevated work. In access equipment, attention to detail is the difference between frustration and flawless operation.