Car Alarms: Using horn instead of siren on car alarm, using a multimeter, car horn

Question
Can you use the car horn instead of the siren that came with the alarm?  I don't have room in the engine compartment to install the siren so I want to connect the car horn for sound on aftermarket alarm.

Answer
Your after market system would need a
horn output wire which is driven
by an internal relay, or you can
determine the polarity using
a multimeter for the horn wire and
see the appropriate relay app. at my site
www.RELAYHELP.com

Look at either a negative
trigger relay or, a positive relay depending
on the polatity of the vehicle's horn wire.

Then the wire needed to drive the relay is the
siren output from the after market.
This will safely honk the horn.

To get the wiring for your vehicle,
go to www.wiringcharts.com

Good luck.

ALARMTEK