do i need a relay or transistor that when 12 v is applied it connects a wire to ground..

Idea for this reason.
Some people like the idea of hearing their horn honk when they hit unlock on their car. So since the keyless module from a firebird/camaro that i sell in the mall can me modded to allow the horn to beep at the same time that you hit unlock it honks the horn

the black wire on the horn relay next to the "blue dingy thingy"

The idea of using a relay generally is, to use it when the device you want to turn on requires more current than powering it directly can handle. This is why signal wires to a relay are so small, and the switch side uses bigger wires. Best example of this on a car is the blower motor.

Looking at the wiring diagrams, I just noticed it actually grounds the wire at the horn, so you would need a relay to convert the power signal to a ground. You'll need a 20A 4 pole relay that is normally open. Try this:



The wiring can all be accessed in the passenger footwell area. Horn relay at the continence center, and the power lock relays are in the same area.

[This message has been edited by RWDPLZ (edited 07-08-2014).]

so would just having one of the unlock signal wires (tan) going from there over to the dark green wire would put 12v to the horns causing them to go off correct? or would i annoy everyone and hook it up to the white convenience wire and have the horn just go off till you open your door kinda funny but could get annoying fast.

If you supply power directly to the dark green wire, bypassing the horn relay, it would sound the horn. If it were me, I'd use the tan 12V door lock actuator wire to trigger the relay in the diagram above, completing the circuit and still using the car's original horn relay.