Brush systems fail mechanically as often as electrically.
Start Here
Remove hair and string unplugged.
Inspect belt if user-serviceable.
Check brush bearings for free movement.
Verify floor-head switch settings.
Look for blockage in the neck.
Appliances rarely fail in a way that names the defective component for you. Brush systems fail mechanically as often as electrically. For vacuum brush does not turn, concentrate on interlocks, compact mechanics and safe external diagnosis. Use every working function as evidence: if one stage still behaves normally, that fact eliminates causes that would have stopped the appliance earlier in the sequence.
Observe the timing before touching anything. Note what happens immediately after Start, what changes just before the fault, and what remains normal afterward. Lights, relay clicks, water movement, motor or fan sounds, heat, vibration and error codes are useful only when tied to a point in the cycle. A fault that appears instantly is a different problem from one that appears only after the machine warms up or reaches a later stage.
Begin with the cheapest conditions to verify: remove hair and string unplugged, then inspect belt if user-serviceable. Do not merely glance at them. Compare the actual condition with the manual, correct anything obviously wrong, and retest before moving deeper. Simple installation, maintenance and user-setting problems regularly imitate failed electrical parts.
If those checks pass, move to check brush bearings for free movement. Then decide whether verify floor-head switch settings can be evaluated safely with power isolated. Choose one test that answers one question: blocked or clear, open or closed, free or jammed, intact or electrically open. If a test result would not change your next decision, the test is probably not worth doing.
Avoid cutting debris near fingers carelessly, running a stalled brush motor, and oiling sealed bearings indiscriminately. All three skip evidence and can turn a minor fault into an expensive one. After a correction, reassemble guards and connectors, restore normal settings, and reproduce the original operating conditions. A single successful start is not proof; the original symptom must stay gone through the stage that used to fail.
A Safe Step-by-Step Check
Document the exact symptom and pay special attention to remove hair and string unplugged.
Remove external causes first; specifically verify inspect belt if user-serviceable.
With power isolated where required, inspect check brush bearings for free movement and then evaluate verify floor-head switch settings only if it can be done safely.
Reassemble fully and run a controlled test under the conditions that previously caused the fault.
Common Beginner Mistakes
Cutting debris near fingers carelessly.
Running a stalled brush motor.
Oiling sealed bearings indiscriminately.
STOP AND GET HELP: If the next useful test requires exposed live mains, defeating a safety interlock, opening a sealed refrigeration circuit, disturbing gas controls, or entering a microwave high-voltage section, the diagnosis has reached the professional-service boundary.