Weston

I bought an alarm and it has an output for a starter kill relay. It turns out that the relay only gets powered when the alarm is armed. I would have to set it up so that it disables the starter when that relay is powered, but that means that a thief could just cut power to the alarm and then the car would start! I e-mailed the people that I bought the alarm from and they said that all alarms (that have a starter kill feature) work that way. Is that true? It just seems pointless to me... If a thief can hot wire my car, then surely he also knows how to pop the hood and cut the big yellow wire that I have powering the alarm. Was I supposed to just hide that wire and trust my car to security-through-obscerety?

I plan to add another relay on the alarm to inverse it's starter kill output, so if the alarm looses power, gets it's wires cut, etc the car still wont start. I'm just wondering if my alarm is normal or not.

CanadaCivicSIR

The whole point on having an Alarm in your car is to slow them down. If a thief really wants your car he is going to try and might succeed in taking it.

Yes all Starter kills work that way.

When installing an Alarm try and make the wiring as invisible as you can, stealth installs are the key. Tape it up and Ty-Rap everything nice and neat.

One thing I do, on important wires for the Alarm under the dash, is tape them in yellow and use yellow tubing, just like the factory uses so the thief thinks those wires are air bag wires.

Try not to wire anything to the battery directly, because that is the easiest spot for a thief to find the wires and cut them. There are plenty of wires under the dash with 12V to supply the alarm with power. The only wires needed to go pass the firewall are the siren wire and hood pin wire. You can also purchase a battery back up siren so if the wires are cut to the alarm, the bat back up siren goes off tell you turn it off with a special key.

There are many accesories alarm companies produce to help out with your alarm such as battery back up devices, prox sensors, glass break sensor and many others.

Just remember that if it is that much harder to steal or break into your car then the car next to yours, chances are the car next to yours will be hit.




[Modified by CanadaCivicSIR, 8:36 PM 1/25/2002]

Weston

Well, crap... I already wired up the alarm with the power coming from the main fuse box in the engine compartment (looked like safest place to connect it). It's extremely obvious, but I figure that if the crook has the hood open, he could just cut the siren anyways, so hiding the alarm's power wire isn't going to keep him from shutting the thing up.

I am going to use an additional relay for the starter cut, so cutting the alarm's power wont re-enable the starter. I'm also thinking about "booby-trapping" that alarm power wire so that if it isn't hot (ie if it's cut), it activates the horn. Oh, fun with relays.

Weston

There's no need to be so condescending. You obviously didn't understand what I was saying. I am well aware of how relays work and know exactly what I am doing. I can't just simply wire a single relay in a NO setup because of the fact that the alarm's output is only hot when armed. I need to use another relay to inverse that output so it becomes hot only when unarmed.

It's very simple... Relay #1 is connected to the alarm's armed output (hot when armed) and uses a NC setup to power relay #2, which uses a NO setup to interrupt the starter. When the alarm is armed, relay #1 cuts power to relay #2, and the starter can't get power. When the alarm is unarmed, relay #1 gives power to relay #2 and the starter will work fine. If the alarm's power is cut (or it's wire bundle is cut), relay #2 can't get power, so it interrupts the starter by default. I already have the relays wired up, I just need to make it interrupt the starter (using the clutch sensor, to be more precise).

All that I wanted to know is if the starter kill of most alarms work in the way that mine does, and apparently they do (according to CanadaCivicSIR and my alarm's seller). In my opinion, it's pretty much pointless to hookup a starter kill in the way intended by the alarm makers, because all you have to do to bypass it is cut the alarm's power (which thieves will do anyways to shut the thing up). Security through obscerety (ie hiding the alarm power wire and hoping that thieves wont find it) is not always a great solution. In my case, the thieves would have to either cut the armed output wire between the alarm and relay or find and reconnect the kill relay's power wires to a constant power source; both are harder and more time consuming than finding and simply cutting the alarm's power wire, hidden or not. Of course, anything can by bypassed, no matter how well installed. But thieves around here aren't very sophisticated.

Eric R

Weston: What Teken is trying to say, and he's right, that it doesn't matter if the thief cuts the power to the alarm or the whole car, the starter kill relay will always work. If you check on the installation manual of your alarm, you might have a diagram of how to wire the starter kill relay to that specific output from the alarm, or maybe not. The thing is that you need to know that the starter disable from the brain (most of the time is an orange wire) is a negative 300ma output while armed type of output. The relay is positively powered only when you try to start the engine from the ignition switch. So, if you know how to wire relays and know the alarm circuit, you should know that the car won't crank up if the power is disconnected. The key is to hide as good as possible the wires and the starter kill relay.

P.S.: Depending on the alarm, we always try to use the main ignition harness as a source of power. It is safer and stealth, unless otherwise specified by the alarm manufacturer, i.e. Clifford - Avital.

95gsr

the thing is that is someone tries to crack the car the relays will click telling to person where they are try wrapping them with something to shut them poo poos down also