Guided by a light-emitting diode (3)
I believe the answer is:
led
I believe this clue is a double definition.
'guided' is the first definition.
(similar in meaning)
'a light-emitting diode' is the second definition.
('LED' can be a synonym of 'light-emitting diode')
'by' is the link.
(Other definitions for led that I've seen before include "Went in advance of others" , "Was guiding" , "showed the way ahead" , "induced to" , "Came first" .)