2005 IMPALA 3400 what I did checked fuses and relay are fine.I don't think problem is in steering column because it also used to wok when I armed it with remote.I checked it by bypassing relay and also switching relay and horns work fine when I trigger from relay I also trigger relay with negative and horns work.I am looking for wiring diagrams for this.Does wiring from steering go to factory alarm or straight to horn relay in hood .Its hard to work with out wiring diagrams,when I trigger panic head lights flash no horn sound.
thanks for any hyelp
Elliot