His left-foot cross was met by Richard Cresswell who headed home his 17th goal of the season.
Wolves hit back immediately and equalised in the tenth minute when Jody Craddock's close-range shot flew into the net after Lee Naylor's free-kick had found the former Sunderland star.
Preston almost regained the lead when Sedgwick let fly from 25 yards out but Wolves keeper Michael Oakes tipped the ball around the post.
Cresswell and Lewis both fired narrowly wide as Preston remained on top.
Paul McKenna's 25-yard shot was then saved by Oakes and the Wolves keeper denied David Nugent on the stroke of half time.
Immediately after the restart Nugent hit the post with a long-range drive and Cresswell fired the rebound wide.
Preston were awarded a penalty in the 53rd minute when Joleon Lescott was adjudged to have fouled Lewis in the box and Graham Alexander fired his penalty into the middle of the net as the keeper dived to his right.
Nugent forced Oakes to make another great save on the hour but against the run of play Wolves equalised in the 73rd minute.
Ki-Hyeon Seol's mazy run ended with the South Korean firing a 20-yard drive into the bottom right-hand corner of the net.