708-7P-00020 / 708-7P-00030 / 708-7W-00230 Komatsu HM400-3 / HM400-5 Fan Motor Core Function Drives the cooling fan to dissipate heat from the engine and hydraulic system. Automatically reduces speed at idle or low temperature to save fuel and reduce noise, and increases speed under high temperature or heavy load to ensure adequate cooling. Common Faults & Troubleshooting Fan not rotating / abnormal speed: First determine whether the fault is in the pump or motor—measure the