Set out to mend taser that's malfunctioning (11)
I believe the answer is:
demonstrate
'set' is the definition.
(thesaurus)
'to mend taser that's malfunctioning' is the wordplay.
'that's malfunctioning' indicates an anagram.
'to'+'mend'+'taser'='tomendtaser'
'tomendtaser' anagrammed gives 'DEMONSTRATE'.
'out' is the link.
(Other definitions for demonstrate that I've seen before include "Show or display" , "Present" , "Prove, show" , "Prove - protest" , "March" .)