This study aims to analyze the influence of implementing Value Stream Mapping (VSM), 5S culture, and lean services on customer satisfaction at the Palembang Workshop Service Unit (UJWP) of PT PLN Nusantara Power Services, with Turnaround Time (TAT) serving as an intervening variable. The research is motivated by the sub-optimal operational performance at UJWP, where the average repair lead time reaches 27 days, significantly exceeding the 14-day Service Level Agreement (SLA) target, and a Customer Satisfaction Index (CSI) of only 68.75%. This study employs a quantitative approach using explanatory research and Structural Equation Modelling - Partial Least Squares (SEM-PLS) to analyze data from 153 respondents selected via purposive sampling. The results indicate that Value Stream Mapping (VSM) and 5S culture have a positive and significant direct influence on customer satisfaction. Conversely, lean services and Turnaround Time (TAT) do not have a significant direct impact on customer satisfaction within this operational context. Furthermore, Turnaround Time (TAT) is not proven to mediate the influence of the lean variables on customer satisfaction. These findings suggest that in the critical power plant repair service industry, customer satisfaction is driven more by process quality, information transparency, workplace organization, and technician professionalism than by repair speed alone. The managerial implications of this study emphasize the necessity for UJWP management to integrate physical aspects and technical capacity into their lean strategy to achieve the established SLA targets.