Horn Relay
WARNING: This page is about a different car, the 2002 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
Remove appropriate relay located behind right side of instrument panel. Check relay continuity. Continuity should exist between relay terminals No. 1 and 2, and also between terminals No. 3 and 4. Continuity should not exist between relay terminals No. 3 and 5. Using fused jumper wires, connect positive battery terminal to relay terminal No. 1 and negative battery terminal to relay terminal No. 2. Continuity should now exist between relay terminals No. 3 and 5. Replace relay if continuity is not as specified.