Horn Relay replaced multiple times in a few months

Do you have an air bag light lit on the instrument cluster ? Do you have C.C. button's on the steering wheel , do they work ? If the alarm fob (as u call it ) Can make the horns sound , the relay is sending B+ voltage to the horns Don't know how your testing.
System Description
The horn system consists of the following components:
• Horn fuse
• Horn relay
• Horn switch
• Horn(s)
• Body Control Module (BCM)
System Operation
The vehicle horns are activated under the following conditions:
• The horn switch is depressed.
• The body control module (BCM) commands the horns on. The BCM commands the horns on under either of the following conditions:
- When the content theft deterrent system detects a vehicle intrusion. For further information, refer to Content Theft Deterrent (CTD) Description and Operation in Theft Deterrent.
- When the panic button is depressed on the remote control door lock transmitter. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry.
- When the OnStar® system is used to sound the horns, if equipped. For further information, refer to OnStar Description and Operation in Cellular Communications.
- When the keyless entry system is used to lock the vehicle, a horn chirp may sound to notify the driver that the vehicle has been locked. The notification feature may be enabled or disabled through personalization. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry.

Circuit Operation
Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing the horn switch applies ground to the horn relay control circuit. The body control module BCM may also apply ground to the horn relay control circuit as described above. When the horn relay control circuit is grounded, the horn relay is energized and battery positive voltage is applied to the horn(s) through the horn control circuit. The horn(s) sound as long as ground is applied to the horn relay control circuit.

your remote is picking up another signal some place and your cars being haunted by it
reset alarm settings
now the other problem is your battery is getting weak loosing its charge because its constantly on simple get charger to trickel charge system or replace battery

If the relay clicks when the horn button is pressed the horn is the problem, if no then the clock spring contact under the steering wheel is defective. The horn is under the car behind the front bumper area.

Excessive use, horns have a very short life span.

do you hear a click sound from a relay when pressing on horn button? most likely is underhood. if so,locate the horn(s) and test voltage with a test light or DVOM at the horn + side. if both have voltage,check - side.(ground).if both are correct replace both horns.

Lets try step by step heck $600 you re-run a new horn. Open your hood, and take the fuse/relay box cover off. Press your horn listen for the relay to click in the box if the relay does not click then it is not triggering. take a paperclip and pull the horn relay and jumper 30 and 87 as seen on the bottom of the relay in its corresponding spots in the panel. Your horn should sound. The last time i ran across this problem was the steering coulmn did not have an adequate ground, checking that could be a simple check of jumper cable to the metal of the column and the battery ground.

replace the horn.thesecurity system should have a seperate horn to the normal "tooting" horn.

Standing out side the car, reach in and push the horn pad. Do you hear a click under the hood?

If not, check your fuse. If the fuse is good, check the relay.

If you do hear the click, your horns have likely failed. You can check for 12 volts with a multimeter or test light on the horn wire when the pad is depressed to verify.
If the relay and fuse check out OK and you still do not have power at the horn wires, your pad may have failed or the wire has come loose from it. This is an airbag component and should not be disassembled without familiarity with airbag systems..

If you do have 12 volts at the wire with the pad depressed, replace your horns.

One horn is located below the drivers headlight.
The other horn is near the firewall on the passenger side.

The "click" is the relay working. look under the front bumper to find the actual horn and replace it. the wire should slide off a pin on the back of the horn.

could just be the actual horn in the car..before i replaced it i would look for a loose wire on the aftermarket alarm though..