auxout

Ok I have a viper alarm blah blah, I would like to make a working starter kill that work with the alarm, the alarm has a provision for this a 500ma ground that comes on(?) when the alarm is armed. How do I wire a relay to kill the starter when the alarm is on? I know basic electronics stuff i have a voltohmeter/multimeter, I already have two wires that will kill the starter, but relays is beyond what I know. So if someone could explain what kind of relay I need and how I wire this deal up I would really appreciate it. Thanks


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1992 RS 3.1
1985 POS (SC 2.8 CFI)

Tim Burgess

Use a Bosch SPDT 30 ampere relay, which should be available from most auto parts stores. Cut the yellow wire that goes from the ignition switch to the neutral safety switch (NSS) (automatic), or clutch start switch (manual) - The hatch release relay wire also connects to the yellow wire on an automatic car, if you have an electric hatch release - before you cut the yellow wore, make sure that the hatch release relay wire is tied to the yellow wire going to the NSS. Connect one end of the cut yellow wire to the NC terminal on the relay (terminal 87A), and connect the other end of the cut yellow wire to the pole terminal of the relay (terminal 30). Connect one of the relay coil wires (terminal 85) to the alarm system output that is grounded when the system is armed. Connect the other relay coil wire (terminal 86) to the yellow wire that goes back to the ignition switch. If an attempt to crank the engine occurs while the alarm system is armed, the relay coil will energize, preventing the starter from engaging.

Tim

TunedPort350

Just thinking outloud here...

This is one thing I never understood about the starter kill output on vehicle alarms. The relay is wired NC so that when the alarm is armed the output comes on and opens the relay contact. So if a thief cuts the power to the alarm (or the control portion of the relay) than the relay is now off and the car can be started.

Any idea why the alarms starter kill outputs aren't designed to use the NO circut. So when the alarm is armed the relay is off (killing start), and when the alarm is disarmed the output is on enabling the starter? This way if a potential thief cuts the power to the alarm or the relay control wires the car won't start.

I imagine your car is off more than it is running so the relay duty cycle would actually be less too.

TunedPort350

One other thing I forgot to mention. I actually thought about adding a second relay to accomplish what I stated above. I would use the first relay to control the second relay. The second relay would perform the starter kill being used as a NO contact.

After thinking about it I decided that I would be better off just using a hidden toggle switch to accomplish this. That is what I did and I feel this is actually the best thing to do. You might want to do the same Auxout. Especially considering you are already going to break this circut with a relay, might as well add a hidden toggle switch while you are there.

Tim Burgess

Yes, it seems that it would be a more robust design if the alarm starter relay disable output was open when the alarm was armed & grounded when the alarm was disarmed. If you use a switch in line with the start circuit it should probably be rated for no less than 15 amperes.

Tim