1993 f150 xl 4x4 4.9L no cruse. My horn relay is not tripping, if I jump the relay contacts without the relay installed the horns sound so the system is good from the relay to the horns. I have tryed: 3 different relays, cleaned all 3 firewall connectors, jumped the wires behind the horn button with no affect, cleaned (very well) the contacts between the steering wheel and steering column, tripple check all fuses and checked what I can reach of the wires. I am out of ideas. Please

 

This just a general post about relays, to trip they need 2 things:

1) +12vdc
2) ground

add 1 at a time till it works - then trace the missing signal

 

Found the falt, no ground coming out of the wireing loom behind the dash that routs to the horn button. I still don't know where the brake in the wire is but I spliced in a new ground and the horn works.