It's right to check when there's sign of something wrong inside (6)
I believe the answer is:
dexter
'it's right' is the definition.
(heraldic term for right)
'something wrong inside' is the wordplay.
'something' becomes 'deter' (I can't explain this - if you can you should believe this answer much more).
'wrong' becomes 'x'.
'inside' means one lot of letters goes inside another.
'deter' enclosing 'x' is 'DEXTER'.
'to check when there's sign of' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
(Other definitions for dexter that I've seen before include "Colin --, detective writer" , "Colin --, Inspector Morse creator" , "Colin -, Inspector Morse author" , "far from sinister?" , "In heraldry, of or on the right side" .)