Diagnosing Control Lag in the Simon 32' All-Terrain Scissor Lift

[MikePhua]

The Simon 32 and Its Off-Road Capabilities
The Simon 32' all-terrain scissor lift was designed in the mid-1990s to meet the growing demand for elevated work platforms capable of operating on uneven terrain. Built with a robust steel chassis, large flotation tires, and a Wisconsin 4-cylinder gasoline engine, the Simon 32 offered contractors a mobile solution for exterior building maintenance, steel erection, and signage installation. Its 32-foot platform height and wide stance made it suitable for rough sites where conventional slab lifts would fail.
Simon Access Equipment, once a respected name in aerial work platforms, was eventually absorbed into other brands, and parts support became limited. However, many units remain in service, especially in rental fleets and small contractor yards.
Symptoms of Sluggish Control Response
Operators have reported delayed or inconsistent control response in steering and drive functions. Specifically:

• Steering left or right requires holding the joystick for several seconds before movement begins
  
• Forward and reverse functions work intermittently, often requiring simultaneous steering input to trigger motion
  
• Controls behave normally when connected to jumper cables or a battery charger
  

These symptoms suggest low voltage delivery to control solenoids, which rely on stable power to actuate hydraulic valves. The fact that external power restores normal function points to an electrical supply issue rather than mechanical failure.
Electrical System and Voltage Drop Diagnosis
The Simon 32 uses a 12V DC electrical system to power solenoids, relays, and control logic. The original battery setup may not provide sufficient cold cranking amps or reserve capacity for sustained operation, especially if the wiring has aged.
Key diagnostic steps include:

• Checking battery voltage under load: A deep cycle battery may hold 13.8V at rest but drop below 11V during operation
  
• Inspecting ground connections: Corroded or loose grounds can cause voltage drop across the control circuit
  
• Tracing battery cable routing: Look for frayed insulation, poor crimps, or undersized wire
  
• Testing solenoid activation voltage: Use a multimeter to confirm that each solenoid receives full voltage when commanded
  

One technician found that the ground strap between the frame and engine block had corroded internally, causing intermittent control loss. Replacing it with a braided copper strap restored full function.
Control Logic and Hydraulic Valve Behavior
The Simon 32 uses electro-hydraulic valves to manage steering and drive. These valves require a minimum voltage threshold to shift spools and direct fluid. If voltage is marginal, the valve may hesitate or fail to engage.
In some cases, the joystick controller itself may have worn contacts or degraded potentiometers. Cleaning or replacing the joystick can improve responsiveness.
Hydraulic fluid condition also plays a role. Cold or contaminated fluid increases resistance and delays valve actuation. Operators should:

• Replace hydraulic fluid annually
  
• Use manufacturer-recommended viscosity
  
• Inspect filters and screens for debris
  

Recommendations for Restoration and Reliability
To restore consistent control response:

• Install a high-capacity starting battery with at least 800 CCA
  
• Replace all ground cables and battery terminals
  
• Clean and tighten solenoid and relay connections
  
• Upgrade wiring to 10 AWG or larger for main power feeds
  
• Test joystick output and replace if voltage is inconsistent
  

For long-term reliability, consider adding a voltage monitor to the control panel and performing seasonal electrical inspections.
Conclusion
Sluggish controls in the Simon 32' all-terrain scissor lift are typically caused by low voltage delivery and aging electrical components. With targeted diagnostics and upgrades to the battery, wiring, and grounding system, operators can restore full functionality and extend the life of this rugged lift. Understanding the interplay between electrical and hydraulic systems is key to maintaining performance in older aerial platforms.