Despite seeing Joel Grant red carded in the first half, Wycombe found themselves two goals to the good inside 50 minutes as Dean Morgan scored twice.
But after pulling a goal back just before the hour through Richard Brodie, Redshaw struck late to salvage a point for Morecambe.
Wycombe started brightly, and took the lead after 21 minutes, as Josh Scowen's long clearance was misjudged by Will Haining on halfway, allowing Morgan to race clear.
Wycombe top-scorer, Grant, then went close with a curling 20-yard shot, before combining with Morgan, who fired over from a similar distance.
But Grant's afternoon was ended early as he saw red for a dangerous tackle on Andrew Wright five minutes before half-time
Despite the numerical disadvantage, Wycombe made it 2-0 in the
49th minute, as Morgan controlled a long ball forward on halfway before turning and beating Nick Fenton for pace and strength for his fifth goal of the season.
But the Shrimps pulled one back before the hour, Brodie heading his sixth goal of the season at the near post from Izak Reid's corner.
And the visitors completed their comeback late on, as their sixth corner of the match was eventually headed in by former Manchester City trainee Redshaw.