Horn wire on valet 712t keyless

I have an 02' Toyota tacoma v6 4wd and purchased a Valet 712t Keyless entry system at Circuit City. They did not hook up the horn output (not sure why). I am trying to do so myself and cannot figure it out. If the key is not in the ignition the horn will still sound when pressed ( I think this means I have a (+) horn....). The install manual says the brown wire on the keyless unit is for the horn, but when I conect it to the horn in the fuse box in the dash tt wont sound the horn when I press the lock/unlock button on the remote. After further testing I found that if I run a wire from the battery to the horn it will not sound when contacted either (horn only has I metal tab on the connecter).

Can anyone help? I am not the best at electrical issues, but have installed stereos, amps, subs etc with no problem... THis can't be that hard.......