Go to the horn relay. Remove it, then in the socket, check first for twelve volts. There should be four terminals and two should have twelve volts all the time. Of the other two, read their resistance to ground. One should have real low resistance. That one is going to the horns. The last one should have close to 0 ohms only when the horn switch is pressed.
If all of those appear to be okay, suspect the relay. Be aware the switch circuit can measure okay if only a single strand of a frayed wire is still intact, but that will not allow enough current through to run the relay's coil.
Also, observe if the relay clicks when you press the switch. If it does, you have just eliminated half the circuit as a suspect.
Tuesday, December 19th, 2017 AT 3:21 PM