Verify Cooling Fan Function in Heavy Traffic

Cost Savings

Checklist Tasks

• Monitor engine temp gauge at idle to check fan activation timing.
• Listen for grinding or irregular fan noises indicating motor or bearing issues.
• Run AC at idle and confirm fan engages properly.
• Inspect fan relay and fuse for heat damage and corrosion.
• Use scan tool to match coolant sensor reading to actual engine temperature.
• Examine wiring at fan motor for loose or melted connections.
• Clear any debris or plastic obstructing fan blades.
• Measure voltage at fan motor terminals under load.
• Check that fan shroud is secure and undamaged.
• Test secondary fan (if equipped) during high load or AC use.
• Inspect temperature switch or module for moisture or shorts.
• Idle with AC on to monitor consistent fan cycling and temperature control.