Reader sees voter blowing top (6)
I believe the answer is:
Here is my best explanation:
'reader' is the definition.
('lector' can be a synonym of 'reader')
'voter blowing top' is the subsidiary indication.
'voter' becomes 'elector' ('elector' can be a synonym of 'voter').
'blowing top' means to remove the first letter.
'elector' with its first letter removed is 'lector'.
'sees' is the link.
(Other definitions for lector that I've seen before include "Person reading lessons in church", "Reader, esp. in church", "Reader at certain universities", "one reads", "Church reader" and "Hannibal - -".)