Here is the language of the amendment of (55 ILCS 5/2-1003) (from Ch. 34, par. 2-1003).
A chairman who is chosen by the county board may be
removed, with or without cause, upon a motion adopted by an
affirmative vote of four-fifths of the county board. Upon
adoption of a motion to remove the chairman: (i) the chairman
position becomes vacant and the former chairman’s compensation
shall be prorated to the date the motion was approved; (ii) the
vice-chairman immediately assumes the duties of chairman
without chairman compensation; and (iii) a new chairman shall
be elected at the next regularly scheduled county board
meeting. A chairman removed under this Section maintains his or
her status as a member of the county board.
Here is the link to the General Assembly Website for the bill. http://www.ilga.gov/legislation/fulltext.asp?DocName=&SessionId=108&GA=101&DocTypeId=HB&DocNum=3593&GAID=15&LegID=120278&SpecSess=&Session=