On a Toyota the fan clutch seal was leaking oil very slowly so the fan was kicking fluids into alternator and filled coil that was built into the top of the starter. When you stopped it would stall. It was so slow that it was not visible till parts filled up with oil and shut the whole electrical system while sitting at a light. Replaced seal and replaced with used rebuilt coil and starter from starter shop as we noticed missing teeth on flywheel. Cleaned alternator and re gelled all electrical connections. Solved that problem. Make sure battery cables are totally cleaned.