Route finder took position before vehicle sent the wrong way (6)
I believe the answer is:
satnav
'route finder' is the definition.
'took position before vehicle sent the wrong way' is the wordplay.
'took position' becomes 'sat'.
'before' is a charade indicator (letters next to each other).
'vehicle' becomes 'van' (van is a kind of vehicle).
'sent the wrong way' is a reversal indicator.
'van' written backwards gives 'nav'.
'sat'+'nav'='SATNAV'
(Other definitions for satnav that I've seen before include "Device for finding one's way" , "Modern substitute for a map" , "Road atlas replacer" , "course-finding apparatus" , "Talking road map?" .)