This invention patent is a utility type of car fan controller. The controller has a housing and inside the housing is a circuit. The housing has a top cover forming a cavity and flat bottom plate. The circuit has a circuit board and an adjustment device with other electronic components. The circuit board has a socket connector and a wire harness connector. The top cover has socket connector aligned with socket connector opening. The top cover also has a wire harness connector aligned to wire harness connector socket. The modular practical new type of invention design facilitates faster assembly and more convenient flexible use.