This has been a problem for quite some time. If the Edge 1040 goes into sleep mode, when it wakes up, it automatically reconnects to the radar sensor for the RTL-515, but not the light. This has been an issue on every Edge and Varia unit I've ever owned (Edge 1000, Edge 1030, Edge 1030 Plus, Edge 1040 Solar, RTL-500, RTL-510, RTL-515).