Horn troubles

[squarebody8620]

Hello I’ve been trying to get my horn working in my 86 gmc k1500 I’m pretty sure I had power at the horn relay n I replaced it, I have no power coming from the black wire to the two green post wires to the horns, is it only when you hit the horn or at all times?

 

[Jgonick]

At the horn relay (in the convenience center) Orange 240 wire brings power from fuse box (horn fuse) to relay. Black 28 wire goes to horn button. When you press the horn button it grounds the black wire which grounds the circuit. This causes the relay to work. (relay is an electric switch) The relay switch is activated and provides power through the Green 29 wire (changes to blk/grn) to the horn. The horn itself should be grounded to metal at the horn.