relay holder corroded ?

ive had to fix a few mk3 mondeos with electrical faults , both to the wipers , 1 was a corroded relay (which when put on the horn circuit worked fine but not on the low load wipers circuit) and the other was a corroded connecter on the relay

both were in the box under the bonnet , not sure if the lights relay is in there or in the cabin without looking

check for power and earth at the relay connectors and also try another relay from another circuit