Perhaps you have not found the applicable fuse, which may be an in-line fuse, not in the main fuse box, on your model? There were so many changes that I can't be quite sure what wiring diagram should apply, but at least the wire colours are always consistent.
To identify the correct fuse, the incoming supply will be a brown wire, while the outgoing feed to the horn and headlight flasher circuits will be purple. Check that there really is battery voltage on the purple circuit, broken or corroded fuse contacts, bullet connectors, etc are not uncommon.
You should find that the low brake fluid level test switch is not working either, as it is usually fed from the purple circuit. It follows that there will be no warning in case of low fluid level. There are usually (varies by model and year) two outgoing wires from the fuse, one goes to the brake warning test switch, and the other goes to the horn and headlight flasher switches on the steering column.