Brush height adjustment error, automatic height control not functioning

Safety: Unplug the unit before working underneath.

• Check for mechanical jams: Inspect the brush head for debris or foreign objects that could block height movement.
• Operate height control: Manually move the height adjustment (if possible) to free any stiffness. Do not force if it is completely seized.
• Listen for actuator: When adjusting height (with power on), listen for the small motor. If it hums but no movement occurs, the gears may be stripped.
• Inspect linkage: Remove the bottom cover and check the linkage between the actuator and brush head. Reconnect any disconnected rods or levers.
• Replace actuator if failed: If the motor does not run at all and receives power, replace the brush height actuator assembly.