Fixed home up, installing a light (6)
I believe the answer is:
nailed
'fixed' is the definition.
(I've seen this before)
'home up installing a light' is the wordplay.
'home' becomes 'in' ('he's home' can mean 'he's in').
'up' says the letters should be written backwards (in down clue: letters go upwards).
'installing' is an insertion indicator (inserted letters are installed).
'light' becomes 'led' (light-emitting diode).
'in' in reverse letter order is 'ni'.
'ni' placed around 'a' is 'nai'.
'nai'+'led'='NAILED'
(Other definitions for nailed that I've seen before include "Firmly attached -- arrested" , "Hit precisely" , "Properly fixed" , "Pinned down, literally with small metal spikes" , "Fastened with spike" .)