Each of nine clues contains a superfluous word. Initial letters of these words spell a word which can be read as an indicator of the unclued lights in each of four columns in the grid.
 

Across

 
1    Position since gossip (5)
4    Quickest spy, holding power, passes time (9)
10    Half-moon-shaped utensil made badly, lacking depth (10)
11    Tax reform’s ending universal indignation (6)
12    Pioneers westward around hot valleys (7)
14    Drizzle in chasm fell irregularly (5)
15    Quite impetuous, gutted fish (5)
16    Man in end releasing a disc (6)
22    Leap covering part carrying current (8)
23    Support...