Troubleshooting and Understanding the Snorkel EMS Control System

[MikePhua]

The Rise of Electronic Management Systems in Aerial Lifts
Snorkel, founded in 1959, became a major player in the aerial work platform industry by offering rugged, reliable lifts for construction, maintenance, and industrial use. By the late 1990s and early 2000s, Snorkel began integrating electronic management systems (EMS) into their machines to improve safety, diagnostics, and operational control. The EMS replaced traditional relay-based logic with microprocessor-controlled modules that monitor inputs, regulate outputs, and enforce safety interlocks.
This shift mirrored broader trends in the equipment industry, where electronic control units (ECUs) became standard in everything from excavators to forklifts. While EMS systems offer enhanced functionality, they also introduce complexity—especially when troubleshooting faults or intermittent failures.
Core Functions of the Snorkel EMS
The EMS in Snorkel lifts typically manages:

• Platform movement (lift, lower, extend, retract)
  
• Drive and steer functions
  
• Emergency stop and override logic
  
• Battery voltage monitoring
  
• Fault detection and error code display
  
• Interlocks for tilt sensors, outriggers, and load limits
  

The system receives input from switches, sensors, and joysticks, processes the data, and activates solenoids or motors accordingly. If any safety condition is violated—such as excessive tilt or low voltage—the EMS will inhibit movement and display a fault.
Common Symptoms of EMS Malfunction
Operators may encounter:

• No response from lift or drive controls
  
• Flashing error codes or beeping alarms
  
• Functions work intermittently or only in one direction
  
• EMS display is blank or frozen
  
• Emergency stop button fails to reset the system
  

These symptoms often point to issues in power supply, ground integrity, sensor feedback, or internal logic faults. Because the EMS is central to all machine functions, even minor electrical problems can cascade into full system lockout.
Diagnostic Strategy and Field Testing
To troubleshoot EMS faults:

• Check battery voltage
  EMS modules require stable voltage, typically above 24V for DC systems. Low voltage can cause erratic behavior or complete shutdown.
  
• Inspect ground connections
  Poor grounding is a leading cause of EMS instability. Clean all ground lugs and verify continuity to chassis.
  
• Test input switches and sensors
  Use a multimeter to verify signal voltage and resistance. Tilt sensors, limit switches, and joystick potentiometers must provide consistent feedback.
  
• Cycle the emergency stop
  Some faults require a full power-down and reset. Hold the E-stop for 10 seconds, release, and re-engage.
  
• Observe LED indicators
  EMS modules often include diagnostic LEDs that blink in patterns to indicate fault codes. Refer to the service manual for decoding.
  

A technician in Arizona once traced a lift failure to a loose tilt sensor connector. The EMS interpreted the signal as a constant tilt violation, locking out all movement. Re-seating the connector resolved the issue instantly.
Component-Level Inspection and Replacement
If diagnostics point to a failed module:

• Remove the EMS unit and inspect for corrosion, water ingress, or burnt components
  
• Check for pin damage on connectors
  
• Replace with a factory-programmed unit—many EMS modules are not field-programmable
  
• Update wiring harnesses if insulation is brittle or connectors are loose
  
• Verify compatibility with joystick and actuator models
  

Some Snorkel models use proprietary EMS units that must be ordered through authorized dealers. Always confirm part numbers and firmware versions before replacement.
Preventive Measures and Long-Term Reliability
To reduce EMS failures:

• Keep battery terminals clean and tight
  
• Avoid pressure washing near control boxes
  
• Use dielectric grease on connectors exposed to moisture
  
• Perform monthly function tests and log any anomalies
  
• Train operators to recognize early signs of EMS instability
  

A facility manager in Michigan implemented a quarterly EMS inspection protocol across 12 lifts. Over two years, fault incidents dropped by 60%, and downtime was reduced significantly.
A Story from the Field
In 2022, a maintenance crew at a stadium in Florida faced repeated EMS faults on a Snorkel lift used for lighting repairs. The lift would intermittently lose drive function, forcing manual retrieval. After weeks of frustration, a technician discovered that the EMS ground wire had been painted over during a cosmetic touch-up. The paint prevented proper grounding, causing voltage spikes. Cleaning the lug and re-securing the wire restored full functionality.
Conclusion
The Snorkel EMS system is a powerful tool for managing lift operations, but it demands clean power, solid grounding, and consistent sensor input. When faults arise, a structured diagnostic approach—starting with voltage and grounding—can quickly isolate the issue. In the world of aerial access, electronic control isn’t just convenience—it’s the backbone of safety and precision. With proper care, the EMS becomes a reliable partner in every lift cycle.