Direct answer
Air-conditioner contactor switches high-voltage power to compressor and fan. Related symptoms include outdoor unit silent, buzzing, chattering or running while off. Those symptoms do not prove the component failed: confirm thermostat demand and external disconnect/breaker state.
What this covers
- central AC and heat pumps
- The exact condition described in the title
- Customer-accessible checks before internal repair or reset
What it does not cover
- ×A different brand, model family or similar-looking code
- ×Internal live-electrical, gas, refrigerant or sealed-system testing
- ×A guarantee that a named component has failed without isolation
Capture the exact state
ReversibleRecord the model, exact code, operating stage and whether the product completes the action this component supports.
Separate the likely fault domains
Reversibleconfirm thermostat demand and external disconnect/breaker state.
Correct only the proven, accessible condition
ReversibleCorrect the external prerequisite first. Replacement difficulty is professional high-voltage work.
Verify once before going farther
ReversibleRepeat the same controlled stage and confirm the symptom and stored code stay gone.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I record first for “Air-conditioner contactor: function, symptoms, testing boundary and repair difficulty”?+
Record the model, exact code, operating stage and whether the product completes the action this component supports.
Does the symptom or code prove a part has failed?+
No. confirm thermostat demand and external disconnect/breaker state.
When should I stop troubleshooting?+
Stop for arcing, heat, welded operation or damaged wiring.
Answer for the exact device and software version shown above.