Signals with the lights (5)
I believe the answer is:
beams
This clue is a double definition.
'signals' is the first definition.
(beam is a kind of signal)
'the lights' is the second definition.
(beam is a kind of light)
'with' acts as a link.
(Other definitions for beams that I've seen before include "Shines" , "Smiles; joists" , "Smiles broadly or sunnily" , "Rays of light" .)