Unloading the trailer (SnowRunner)

Please tell me how to unload the cargo from the trailer? It is necessary to bring the repair parts. In order not to drag through the entire map, to the warehouse, I hooked a trailer with this cargo (there is one cell with the cargo that is needed, and the other cell is not.) Also on the map, this trailer was blinking with a yellow square. I drive up to the place of unloading and .... nothing. There is a load in the trailer, but I cannot unload it ....