When your 2020 Infiniti QX60's heater fan stops working, no air moves through the climate system regardless of temperature settings. Without airflow, neither heating nor cooling can reach the cabin. Diagnosing whether the blower motor, its control circuitry, or electrical supply has failed determines the repair path.
Blower Motor Function
The blower motor is an electric fan that forces air through the HVAC system. Located inside the dashboard, typically on the passenger side, it draws air through the cabin filter and pushes it across the evaporator or heater core before exiting through the vents. Without this motor, the system has no means to move air.
Complete Blower Failure
When the blower doesn't work on any speed setting, the motor itself, its power supply, or ground has failed. A motor can fail from worn brushes, burned windings, or seized bearings. Testing for voltage at the motor connector while commanding operation identifies whether power reaches the motor.
Partial Speed Failure
If the blower works on some speeds but not others, the blower motor resistor or electronic controller has likely failed. These components regulate motor speed. High speed typically bypasses the resistor, so a motor that only works on high indicates resistor failure while other components remain functional.
Relay and Fuse Check
The blower motor circuit includes a fuse and often a relay. A blown fuse causes complete blower failure. The fuse location is documented in your owner's manual. If the fuse blows repeatedly after replacement, a short circuit exists that must be found before replacing the fuse again.
Control Input Issues
The climate control panel sends signals to the blower motor circuit. If the panel fails or communication is disrupted, the blower may not receive operation commands. Testing involves verifying signals leave the control panel when fan speed is adjusted.
Diagnostic Approach
Start with fuses—the simplest cause. If fuses are good, check for power at the blower motor connector. If power is present but the motor doesn't run, the motor has failed. If no power reaches the motor, trace the circuit back through the resistor, relay, and control panel.