This study presents an original yield mapping approach based on retrofitted low-cost and easy to implement tracking devices used to monitor the whole harvesting process in viticulture. This method consists of recording the geolocation of all the machines (harvest trailers and grape harvester) during the harvest to spatially re-allocate grape mass of each harvest trailer measured at the winery. The method was tested on a vineyard of 30 ha during the whole 2022 harvest season. Results validate the possibility of making yield maps automatically solely from the time and location records of the vehicles. They also highlight the limitations in terms of spatial resolution of the resulting yield maps which depends on the actual yield and size of harvest trailers.