Electronic wheels on back of car in use again (7)
I believe the answer is:
recycle
'use again' is the definition.
(to recycle something is to use it again)
'electronic wheels on back of car' is the wordplay.
'electronic wheels' becomes 'e-cycle' (electronic bicycle).
'on' means one lot of letters go next to another.
'back of' suggests the final letters.
The final letter of 'car' is 'r'.
'ecycle' after 'r' is 'RECYCLE'.
'in' is the link.
(Other definitions for recycle that I've seen before include "Process for further use" , "To use up left-overs" , "Keep and use again" , "Convert waste to new usage" , "salvage for further use" .)