Check warning light in room (7)
I believe the answer is:
chamber
'room' is the definition.
(chamber is a kind of room)
'check warning light' is the wordplay.
'check' becomes 'ch' (I've seen this in other clues).
'warning light' becomes 'amber' (I've seen this before).
'ch'+'amber'='CHAMBER'
'in' acts as a link.
(Other definitions for chamber that I've seen before include "Judge's room" , "Room for the judge or the bed" , "A formal room as for judge" , "Large room" , "Compartment" .)