Fan, perhaps, of decommissioned vehicle? (9)
I believe the answer is:
extractor
'fan perhaps' is the definition.
(extractor fan is a type of fan)
'decommissioned vehicle?' is the wordplay.
'decommissioned' becomes 'ex'.
'vehicle?' becomes 'tractor' (tractor is a kind of vehicle).
'ex'+'tractor'='EXTRACTOR'
'of' is the link.
(Other definitions for extractor that I've seen before include "Device for removing air from a space" , "Sort of fan" , "Remover" , "Eg, kitchen fan" , "Juice-maker" .)