Wipers only work on fast speed?

Hi, i have a ford KA, 2003, I have found the wipers dont work at all on intermittent, stop after 2 or 3 sweeps if i am lucky on slow without parking at bottom, but work okay with the exception of a failing to park (ie just stop where is switch the off). Removed relay and tried and found nothing changes with wiper relay removed.

any ideas what could be the problem??