Diagnostic Aids
WARNING: This page is about a different car, the 1999 Pontiac Grand Am and 1999 Oldsmobile Alero. However, it is still accessible from the selected car via links, so may be relevant.
If DTC is history, problem may be intermittent. Perform test procedure while wiggling wiring and connectors. Visually inspect connectors and circuits. Check for sticking horn pad or switch. Using DVOM, compare scan tool values to actual BCM values. An open circuit will cause horn to be inoperative. A shorted circuit will cause horn to sound until fuse blows.