Fowler, signed on loan from Conference Premier Nuneaton, gave the Red Devils their first win for 16 games in all competitions with a 20-yard volley three minutes from time.
Winger Kyel Reid was twice off target for Preston before midfielder Anthony Wordsworth gave Crawley the lead on is home debut in the 16th minute.
Lewis Young set up the goal with a quick break down the right and his cross was bundled in at close range by Wordsworth after keeper Sam Johnstone had parried his initial effort.
Leading scorer Izale McLeod threatened for the hosts with a powerful run before firing narrowly over with only Johnstone to beat.
Crawley keeper Lewis Price saved a deflected shot from Reid at the other end after the Preston man ran through unchallenged.
Paul Huntington had a header tipped over by Price before putting his side level by heading in a corner from Paul Gallagher at the near post 11 minutes after the interval.
Preston keeper Sam Johnson did well to parrying a goal-bound free kick from Jimmy Smith, and Crawley defender Lanre Oyebanjo had a shot cannon back off the crossbar nine minutes from time.