Made an effort to be heard (5)
I believe the answer is:
tried
This clue is a double definition.
'made an effort' is the first definition.
(I've seen this in another clue)
'be heard' is the second definition.
(heard or tried in a court)
'to' acts as a link.
(Other definitions for tried that I've seen before include "Made an effort" , "Essayed" , "Proven by experience" , "Made an attempt" , "heard in court" .)