Fix fire, adjusting temperature (5)
I believe the answer is:
refit
'fix' is the definition.
(to refit is to repair)
'fire adjusting temperature' is the wordplay.
'adjusting' indicates an anagram.
'temperature' becomes 't' (abbreviation).
'fire' anagrammed gives 'refi'.
'refi'+'t'='REFIT'
(Other definitions for refit that I've seen before include "Replace or repair equipment as part of a general overhaul" , "Restoration and repair of equipment etc" , "dockyard job" , "Updating or repair process for a ship" , "Overhaul (ship's equipment)" .)