Morgan Syncro Track SX-70 Wiring Overview

[MikePhua]

Background on the Morgan Syncro Track SX-70
The Morgan Syncro Track SX-70 is a tracked utility vehicle first introduced in the early 1980s by Morgan Engineering, a company founded in the 1960s specializing in compact tracked machines for forestry, snow, and off-road industrial applications. Designed for maneuverability in rough terrain, the SX-70 featured a synchronous track system providing equal traction on both tracks while minimizing slippage. The vehicle sold in limited quantities, with an estimated 400–500 units distributed across North America and Europe. It is notable for its robust hydraulic and electrical integration, combining engine, track drive, and implement controls through a compact wiring system.

Electrical System Design
The SX-70’s electrical system is centered around a 12-volt DC battery, which powers:

• Ignition and starter motor
  
• Hydraulic solenoid controls for track and implement movement
  
• Lights and auxiliary equipment
  
• Instrumentation including tachometer, hour meter, and warning indicators
  

The wiring harness is designed to be modular, allowing for easier maintenance and replacement of sections without dismantling the entire harness. Key components include:

• Main fuse panel with 10–15 A fuses
  
• Solenoid bank controlling hydraulic valves
  
• Key switch with run, start, and off positions
  
• Ground bus connecting chassis and engine
  

Wiring Challenges and Common Issues
Owners often report the following electrical problems due to age and use:

• Corroded connectors: Moisture and vibration can cause poor contact, leading to intermittent loss of power to solenoids or lights.
  
• Worn insulation: Chafing along frame edges can expose wires, increasing short-circuit risk.
  
• Faulty key switch: Mechanical wear can prevent the start position from properly energizing the starter solenoid.
  
• Incorrect modifications: Previous owners may have added aftermarket lights or pumps without proper relay protection, causing blown fuses.
  

Recommended Diagnostic Approach

1. Visual Inspection
   • Check the main harness along the track frames, engine compartment, and cab for broken wires or loose connectors.
     
   • Look for corrosion on battery terminals, solenoid posts, and fuse panel.
     
2. Continuity Testing
   • Use a multimeter to check continuity from the battery positive to each major component.
     
   • Verify that grounding points are clean and tight; poor grounds can mimic blown fuses or failed components.
     
3. Solenoid Function Check
   • Each hydraulic solenoid should activate when the corresponding switch is engaged.
     
   • Measure voltage at the solenoid terminals; nominal operation should be 12 V ±0.5 V.
     
4. Fuse and Relay Verification
   • Inspect all fuses visually and test with a multimeter.
     
   • Replace any missing or incorrectly rated fuses.
     
   • Relays should click when energized; a failed relay may need replacement or cleaning of contacts.
     

Solutions and Upgrades

• Harness Refurbishment: Replace brittle wires and use heat-shrink sleeves for improved durability.
  
• Connector Upgrade: Replace older push-on terminals with weatherproof Deutsch connectors to reduce corrosion risk.
  
• Fuse Panel Modernization: Consider adding a secondary relay/fuse module to handle auxiliary loads without overloading the main panel.
  
• Documentation: Create a wiring diagram if one is not available; mark all wire colors, gauge sizes, and terminal types for future reference.
  

Practical Tips for Owners

• Label all wires during inspection or repair to prevent reconnection errors.
  
• Maintain a small stock of fuses, connectors, and standard wire types on hand.
  
• Test electrical circuits with the engine off whenever possible to prevent hydraulic accidents.
  
• Regularly check battery condition and charging voltage to avoid low-voltage issues that can affect solenoid operation.
  

Conclusion
The Morgan Syncro Track SX-70’s electrical system, while compact and efficient, is prone to age-related wear, connector corrosion, and wiring damage. Proper documentation, systematic diagnostics, and preventive upgrades such as weatherproof connectors and refreshed wiring harnesses can dramatically improve reliability. Understanding the layout and function of each component is critical, especially for operators maintaining vehicles in remote or harsh conditions. With careful attention to wiring integrity and voltage verification, the SX-70 can continue to operate safely and effectively decades after production.