Step1: Disconnect power supply to avoid electrical shock or injury.
Step2: Remove old switch and note wiring positions carefully.
Step3: Connect terminals to corresponding SPDT tab switch lugs securely.
Step4: Secure switch into panel opening firmly in place.
Step5: Reattach wiring ensuring tight electrical connections.
Step6: Restore power and test on/on switching operations.
Step7: Ensure insulation and safety grounding are intact before use properly.
Step8: Verify circuit is de-energized and follow electrical safety precaution.