Originally Posted by kanarrjl
Umm no you guys are wrong all except for tonyhatchetman and he would only be right if it uses an external relay. Now let me explain... When properly installed an alarm system has starter kill and will only alow the vehicle to start when disarmed
I'm an installer, its what i do for a living. The relays for the starter kills require 2 things to kill the starter: 1) 12v+ through the ignition wire and 2) a ground via the alarm. A relay is only able to operate when it detects both a +12V and a ground on terminals 85 and 86 receptively. When the fuse is pulled, or the brain is just disconnected from the wiring, the internal relays of the alarm can no longer function and therefore can no longer send that ground to the relay. The result is that the alarm is no longer able to function as a starter kill, or function at all for that matter.
This is why it is highly important to locate the brain of an alarm in a hard to find location. If you are able to easily find the brain, you can VERY EASILY disable any alarm by simply unplugging it.
Just as a little added info, a stater kill on an alarm only cuts the starter circuit when an alarm is set off by powering up the ignition. Setting off the shock sensor or opening a door, or setting off any other sensors will not trigger the starter kill to activate.