Replace the relay with a variable intermittant one from a MK3. The old one will have '19' printed on it, and the variable ones have '99' on em. If it doesn't fix it at least when you do you'll have variable intermittant wipers 
hold on. So if i go to a scrappy, find a mk3, and look at the relays, i should get the one that says "99"? and then i can do the intermitent thing??