Wipers; Could be a faulty stalk control, faulty relays, water getting into places it shouldnt and creating a circuit....
Dash; Could be a loose/faulty connection on the back of the dash unit, or loose/faulty connection down at the fuse box, bad earth...
quite a few different things can cause these im afraid. just have to get stuck in, pull it apart and see what you can find
. Im still chasing my brake/tail light issue!
Rob.