Symbol 1558 from ISO 7000 - Title/Meaning: Fifth wheel, longitudinal adjustment Function/description: To identify the control that activities the adjustment which allows the fifth wheel to move fore or aft into connecting position.
Application referenced in: ISO 2575
Additional information: 
On road vehicles: red telltale indicates fifth-wheel slide unlocked.
Own work using: iso.org/obp/graphics/grs/26c918a5-1d8a-4599-a682-94ed25747a9e 200.png
Vectorization:  Mrmw