83 300 sd turbo. Battery is being drained by fuse 13 which points to central locking system which is one of the circuits on this fuse line, along with seat memory and clock . The memory system never did work properly and the clock works only occasionly. But the battery drain started more when the door lock system stopped working. Is there a electronic unit or relay that activates the vacuum doorlock system, that could be responsible for this drawing power? If so where is it located? Thanks