500sl fuse blowing

Hi,
While driving at night in the rain i used my
washer jets and fuse 13(8a) blew. I have tried 3 fuses since then but they blow as soon as i turn on the side lights. This fuse controls 2 license plate lights,drivers rear light,one headlight,dashboard lights, and what i think is the cause, the headlamp wipers(which only work if the lights are on anyway). Where are the relays for the car i can find no mention in the handbook??
Hope you can help
Mark Maguire