can anyone help ?my bongo failed mot due to 3 things ,brake lights not working i fixed this .horn not working and side repeater on offside not flashing.i have seen some info on horns not working but dont understand it too clearly,i have checked horn is working by putting two wires from the battery to it

i have looked in the relay box and tried to connect a live wire to the relay as suggested by somebody with same problem but that only succeeded in turning fan only, which relay is the horn connected to anybody know?
help please and can i cut off the side repeaters on the wing and cover up the holes with a sticker?