bull dog deluxe 500, xk01, 05 trailblazer

I am using a XK01, but my horn wont sound off when the alarm is tripped.

I am using a Bull Dog Deluxe 500 with the XK01. If I push door lock twice (on the Bull Dog remote) the Trailblazers horn does sound off (six times, not adjustable!) 

The factory locked icon does light on the dash and the aftermarket warning light does flash. 

Now if I open the door without disarming the vehicle, the factory icon flashes fast (so I know the alarm is going off) but there is no horn.

Any ideas? I am suspecting the XK01 has done such a good job of bypassing the security that the horn wont sound!

This is a 2005 Trailblazer.

How did you hook the horn output of the Bulldog up?  I believe the XK01 handles OEM security, not the aftermarket security. 

I would hook up the bulldog's horn output to the vehicle horn wire and retest.