When we found the battery , there were so many wires , we didn't want to risk disconnecting it, we also couldn't find the code for the radio. The fuse had been out for a couple of days and the van has been parked up on a campsite , so we just put the fuse back and hey presto , the wipers are working again. It has been very hot here on the Algarve , so that might have been part of the cause. I don't know what fixed it . Thanks for the suggestions .