How Does a Car Alarm Work?

Video Transcript

"Good afternoon my name is Tom Brintzenhofe, Certified Master Mechanic, out of Reading, Pennsylvania and today we are going to talk a little bit about how car alarms work. Now they have several different sensors in them all hooked to a central box, a brain if you will. A lot of times you will see sensors underneath the hood a little push button sensor the on or off as you open your hood. If a thief opens your hood it opens that circuit up and it is going to trip your alarm. As for your doors if they break in the side of your vehicle they will probably open a door or whatnot. They are usually wired into the dome light switch so you know any door you might open the light comes on and it will trigger the alarm. The other sensors that might be used are motion sensors. If somebody is shaking your vehicle or if it is towed and if you have got it parked alongside the road and somebody illegally picks it up and tows it and tries to steal it the alarm will go off because that is obviously a motion sensor within it and they are usually crystals. Outside of that there is really not much to an alarm. Like I said they run on a few sensors, one on the hood and usually have one on the interior for a door light switch. They will have a motion sensor if somebody tries to move your vehicle. Most of the time they will have what they call a starter interrupt. If somebody does break into the vehicle if it is not key coded and they don't have the pass word or whatnot the remote let's just say it was the whole ignition system so the vehicle cannot start. That is basically what it comes down to with the vehicle alarm and how they work."