Electrical Troubleshooting on the Bobcat 773G Skid Steer

[MikePhua]

The 773G’s Role in Bobcat’s Compact Loader Line
The Bobcat 773G is part of the G-series skid steer loaders introduced in the early 2000s, representing a leap forward in operator comfort, hydraulic performance, and electronic integration. With a rated operating capacity of 1,750 pounds and a 46-horsepower liquid-cooled diesel engine, the 773G became a popular choice for contractors, landscapers, and municipalities. Its compact footprint and vertical lift path made it ideal for loading trucks, grading, and utility work in confined spaces.
Bobcat Company, founded in 1947 in North Dakota, pioneered the skid steer concept and has sold millions of units globally. The G-series marked a transition toward more sophisticated electrical systems, including digital displays, safety interlocks, and electronic fuel shutoff controls. While these upgrades improved functionality, they also introduced new diagnostic challenges.
Understanding the Electrical System Architecture
The 773G uses a 12-volt electrical system powered by a standard lead-acid battery and regulated by an alternator. Key components include the ignition switch, starter solenoid, fuse panel, relays, and the machine control unit (MCU). Safety features such as seat bar sensors, neutral start switches, and hydraulic lockouts are electronically monitored.
Terminology note:

• MCU (Machine Control Unit): The central processor that manages electrical signals and safety logic.
  
• Interlock System: A safety mechanism that prevents hydraulic function unless specific conditions are met.
  
• Ground Fault: An unintended electrical path to ground, often causing erratic behavior or component failure.
  

The wiring harness connects all major components and is routed through the frame and cab. Over time, vibration, moisture, and heat can degrade insulation or loosen connectors, leading to intermittent faults.
Common Symptoms of Electrical Failure
Operators may encounter several electrical issues on the 773G:

• Machine fails to crank or start intermittently
  
• Display panel flickers or goes blank during operation
  
• Hydraulic functions are disabled despite seat bar engagement
  
• Battery drains overnight or fails to hold charge
  
• Fuses blow repeatedly without clear cause
  

In one case, a contractor in Michigan found his 773G would not start unless the seat bar was lifted and lowered multiple times. After inspecting the wiring, he discovered a corroded connector beneath the seat that was intermittently breaking the interlock circuit. Cleaning and resealing the connector resolved the issue.
Diagnostic Steps and Inspection Tips
To troubleshoot electrical issues on the 773G:

• Begin with a visual inspection of battery terminals, ground straps, and fuse panel
  
• Use a multimeter to check voltage at the ignition switch, starter solenoid, and MCU
  
• Test continuity across safety switches and interlock circuits
  
• Inspect wiring harness for abrasion, pinching, or rodent damage
  
• Wiggle connectors while monitoring voltage to detect intermittent faults
  

If the machine fails to crank, verify that the neutral start switch is functioning and that the seat bar sensor is sending a valid signal. For display issues, check the power supply to the panel and inspect the MCU for signs of moisture intrusion.
Repair Procedures and Preventive Measures
Once a fault is identified:

• Replace damaged connectors with weather-sealed replacements
  
• Clean corroded terminals using electrical contact cleaner and dielectric grease
  
• Secure loose wires with zip ties and protective loom
  
• Replace blown fuses only after identifying the root cause
  
• Test the system after each repair to confirm resolution
  

Preventive tips:

• Inspect electrical components monthly, especially in wet or dusty environments
  
• Keep battery terminals clean and tight
  
• Avoid pressure washing near the fuse panel or MCU
  
• Use anti-corrosion spray on exposed connectors
  
• Label wires during repairs to avoid misrouting
  

One operator in Alberta added a secondary ground strap from the battery to the frame, improving starting reliability and reducing voltage drop during cold weather.
Design Evolution and Manufacturer Insights
Later models like the Bobcat S185 and S590 introduced improved wiring harness routing, sealed connectors, and CAN-based communication. These upgrades reduced the frequency of electrical faults and simplified diagnostics. However, the 773G remains widely used due to its mechanical robustness and parts availability.
Sales data from 2024 indicates that over 50,000 units of the 773G series are still in operation globally, especially in rental fleets and owner-operator businesses. Bobcat continues to support these machines with updated service manuals and retrofit kits.
Conclusion
Electrical issues on the Bobcat 773G can be frustrating, but they’re often solvable with methodical inspection and basic tools. Understanding the interlock logic, tracing voltage paths, and maintaining clean connections are key to keeping the machine reliable. With a little patience and attention to detail, even the most stubborn electrical gremlins can be chased out—restoring the 773G to the dependable workhorse it was built to be.