Despite the advancements in artificial lighting technology, such as LEDs, a gap persists between expected and actual performance outcomes, attributed to conventional reliability evaluation methods that inadequately mirror real-world operational conditions. This study explores the crucial roles of failure analysis and fault diagnosis in improving lighting source reliability. It reveals a focus on LED lighting failure analysis based on test data, highlighting a disconnect from operational fault diagnosis. By detailing fault types and diagnostic tools, the study proposes a practical fault diagnosis framework. This framework aims to enhance lighting reliability by incorporating diagnostic insights back into the design and manufacturing stages, creating a closed-loop system between failure analysis and fault diagnosis. This approach bridges the gap between theory and practice, advancing lighting reliability in public libraries. However, the insights into failure analysis and fault diagnosis can be applied to other scenarios.