The wire coming down the steering column is black, and leads to a 10 pin connector that usually clip mounts to the column. The horn lead is pin #28, or "G". The connector has 6 pins on one side, and 4 on the other. The horn contact wire is the 3rd pin from the end, on the four-pin side of the connector. To test if the horn pad contacts are working properly, disconnect this column connector from the underdash lead, and connect a test light to a known hot lead, then touch to pin 28. Hit the horn pad, and the test light will light. If not, either the horn contacts are inop or your column isn't grounded where it is mounted. This black lead is used as a switchable ground source for a horn relay (a must!) All you need to complete this gig is a horn or horns, and a 4 terminal relay of appropriate amp rating. Best regards!
