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Bobcat S175 No-Start Diagnosis and Electrical System Recovery
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The Bobcat S175 and Its Compact Loader Legacy
The Bobcat S175 skid steer loader was introduced in the early 2000s as part of Bobcat’s mid-frame lineup, designed for landscaping, construction, and agricultural tasks. With a rated operating capacity of 1,750 lbs and a 46 hp Kubota diesel engine, the S175 became one of the most popular models in its class. Its compact footprint, vertical lift path, and reliable hydraulic system made it a staple in rental fleets and owner-operator businesses across North America and Europe.
Bobcat Company, founded in North Dakota in 1947, pioneered the skid steer concept and has sold millions of loaders globally. The S175 was produced during a period of rapid growth, with thousands of units shipped annually. Its electrical system, while relatively simple, includes safety interlocks, relays, and a controller that can complicate troubleshooting when the machine fails to start.
Core Specifications
  • Engine: Kubota V2203-M, 4-cylinder diesel
  • Power output: ~46 hp
  • Operating weight: ~6,200 lbs
  • Hydraulic flow: ~16.9 GPM standard
  • Electrical system: 12V with controller and interlock relays
  • Safety features: Seat switch, lap bar sensor, starter interlock
Terminology Notes
  • Interlock Relay: A relay that prevents starter engagement unless safety conditions are met.
  • Controller: An electronic module that manages inputs from switches and sensors.
  • Ground Strap: A braided cable connecting the engine block to the chassis for electrical grounding.
  • Solenoid: An electromagnetic switch that activates the starter motor.
Symptoms of No-Start and Initial Observations
Operators have reported that the S175 fails to crank or start, even with a fully charged battery. The dash lights may illuminate, but the starter remains silent. In some cases, the glow plug indicator functions normally, but the machine does not respond to the key switch. These symptoms suggest a failure in the starter circuit, interlock system, or grounding path.
Common causes include:
  • Corroded or loose ground strap
  • Faulty starter solenoid or relay
  • Damaged controller or wiring harness
  • Failed seat or lap bar sensor
  • Ignition switch malfunction
Anecdote from the Field
In rural Ontario, a contractor’s S175 refused to start after a rainy week. He checked the battery and found it fully charged. After inspecting the ground strap, he discovered it had corroded and detached from the frame. Replacing the strap restored the starter circuit, and the machine fired up immediately. He later added a secondary ground cable to prevent future issues and began applying dielectric grease to all exposed terminals.
Diagnostic Strategy and Repair Recommendations
  • Inspect ground strap for corrosion, fraying, or loose connections
  • Test voltage at starter solenoid with key in START position
  • Bypass interlock relay temporarily to confirm starter function
  • Check seat and lap bar switches for continuity
  • Inspect controller for signs of water intrusion or burnt traces
  • Replace ignition switch if voltage fails to reach solenoid
Recommended Tools and Materials
  • Multimeter with continuity and voltage settings
  • Jumper wires with inline fuse for bypass testing
  • Wire brush and terminal cleaner
  • Replacement ground strap and dielectric grease
  • OEM wiring diagram for S175 electrical system
Preventive Maintenance and Operator Tips
  • Clean and tighten battery terminals monthly
  • Inspect ground connections quarterly
  • Avoid pressure washing near electrical connectors
  • Test safety switches during pre-shift checks
  • Keep spare relays and fuses in the cab or toolbox
Recommendations for Technicians and Fleet Managers
  • Document all electrical repairs and part replacements
  • Train operators to recognize interlock symptoms
  • Retrofit sealed connectors in high-moisture environments
  • Use OEM or high-quality aftermarket components
  • Maintain a fault log and update after each service
Conclusion
The Bobcat S175’s no-start condition is often rooted in electrical grounding or interlock failures. By methodically inspecting the starter circuit, safety switches, and controller inputs, technicians can restore function and prevent future downtime. In compact loader operations, reliability begins with a clean ground—and every start is a signal that the system is ready to work.
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