Being cut off is dire, all new connector leads must be installed (9)
I believe the answer is:
severance
'new connector leads must be installed' is the definition.
I can't tell whether this definition defines the answer.
'being cut off is dire all' is the wordplay.
'being cut off' means to remove the last letter.
'is dire' becomes 'severe' (I've seen this in another clue).
'all' becomes 'ance' (I can't justify this - if you can you should believe this answer much more).
'severe' with its last letter taken away is 'sever'.
'sever'+'ance'='SEVERANCE'
Can you help me to learn more?
(Other definitions for severance that I've seen before include "split" , "Detachment" , "Dismissal from employment" .)