Ask which exact part reference is unavailable and whether the manufacturer lists an approved replacement. A component being absent from one retailer's stock is different from the manufacturer confirming that no supported replacement exists.
What the observation tells you
Used parts or visually similar alternatives can introduce uncertainty about condition and compatibility, especially in controls and mounting assemblies. Do not accept a workaround that bypasses a protective function. Ask how the proposed option affects the reliability of the whole repair.
A useful next step
Keep the diagnosis separate from availability information. Once both are clear, you can assess the practical options without buying speculative parts that cannot complete the repair.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.