Kill Switch - how to wire?
The best kill switch option will depend on what you want to accomplish and what modifications you have made to your car.
If you want to prevent a parked car from being started and it has the stock VATS or you have done a bypass without programming the PCM then the easiest and most effective option is to put a switch in one of the VATS key resistor wires connected near the BCM. This will disable the starter as well as the fuel enable signal to the PCM, so even if a thief gets it to start, it won't continue to run without fuel. This is the theory behind VATS. Putting a switch in that connection means that your ignition key (or bypass) won't be seen by VATS. Even if the thief is smart enough to have one of those VATS bypass modules in an attempt to steal a stock car, it won't work because the connection is cut off by your switch further "downstream". Yes, if they tow your car and have time to work on it somewhere else, they could get it to run, but that's not the purpose of a kill switch... you want them to give up and move on to an easier target.
Another option would be a switch in the clutch switch or neutral safety switch wiring (depending on transmission type) which will prevent starting. The clutch switch would be fairly easy, the neutral safety switch not so much.
A switch wired to the IGN fuse or the fuel pump relay under the hood would prevent the car from running but be a little more work to install. You'd have to run your wiring through the firewall to your switch and the IGN fuse is high current so you'd need heavy gauge wire, or better yet a relay. You'd also want to do a good job of disguising your wiring since, once a thief is in your car, it's no problem for them to pop the hood and have a look for add-on wiring.
The most important thing is to make sure your switch and wiring are well hidden. The best way is to use a factory switch. For example, in a Camaro, you can add a second fog light switch. In a Firebird you can add a convertible top or traction control switch with a latching relay (since they are momentary switches). If you don't ever use your manual dome light switch then you can use it as a kill switch. The dome light switch is triggered by turning the dimmer dial all the way up, but it's actually wired separately from the dash lights. You'll have to add a relay to reverse the polarity (i.e. you want it to turn off something when the switch is turned on and vice versa), but that's really quite easy. And no thief is going to suspect the dash dimmer is a kill switch.
If you want to prevent a parked car from being started and it has the stock VATS or you have done a bypass without programming the PCM then the easiest and most effective option is to put a switch in one of the VATS key resistor wires connected near the BCM. This will disable the starter as well as the fuel enable signal to the PCM, so even if a thief gets it to start, it won't continue to run without fuel. This is the theory behind VATS. Putting a switch in that connection means that your ignition key (or bypass) won't be seen by VATS. Even if the thief is smart enough to have one of those VATS bypass modules in an attempt to steal a stock car, it won't work because the connection is cut off by your switch further "downstream". Yes, if they tow your car and have time to work on it somewhere else, they could get it to run, but that's not the purpose of a kill switch... you want them to give up and move on to an easier target.
Another option would be a switch in the clutch switch or neutral safety switch wiring (depending on transmission type) which will prevent starting. The clutch switch would be fairly easy, the neutral safety switch not so much.
A switch wired to the IGN fuse or the fuel pump relay under the hood would prevent the car from running but be a little more work to install. You'd have to run your wiring through the firewall to your switch and the IGN fuse is high current so you'd need heavy gauge wire, or better yet a relay. You'd also want to do a good job of disguising your wiring since, once a thief is in your car, it's no problem for them to pop the hood and have a look for add-on wiring.
The most important thing is to make sure your switch and wiring are well hidden. The best way is to use a factory switch. For example, in a Camaro, you can add a second fog light switch. In a Firebird you can add a convertible top or traction control switch with a latching relay (since they are momentary switches). If you don't ever use your manual dome light switch then you can use it as a kill switch. The dome light switch is triggered by turning the dimmer dial all the way up, but it's actually wired separately from the dash lights. You'll have to add a relay to reverse the polarity (i.e. you want it to turn off something when the switch is turned on and vice versa), but that's really quite easy. And no thief is going to suspect the dash dimmer is a kill switch.
Joined: Nov 2003
Posts: 11,328
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From: Jacksonville, FL (originally from Toronto Canada)
As in all 97+ f-bodies, the BCM is located under the dash on the passenger side above the glovebox. It has three connectors - a green 6-pin, a black 6-pin, and a blue 32-pin. The wires for the key resistor reading circuit are purple/white and white/black. Both are in the blue 32-pin connector. There are two rows of 16 pins in the connector, labeled C and D. The purple/white wire is in position C2 which is the second position from the edge of the connector. Be careful, because there is another purple/white wire almost beside it (the order starting at the edge position is black, purple/white, empty, purple/white). The second purple/white wire (at position C4) is for the fasten seat belt warning light, so the world wouldn't end if you cut it by mistake - but it wouldn't do any good for your kill switch. The white/black wire is near the middle of the other row D at D7. There is only the one white/black wire in the connector so it might be easier to identify. Just have plenty of light available because there are a number of black/white wires that could look similar.
You only have to cut and splice one of the two wires to connect to your switch. It's a circuit which requires both the feed and return wires to function so having either wire interrupted is enough to disable the circuit and cause VATS to prevent starting.
The easiest and most effective disguised switch for a Camaro is a second fog light switch. The dash opening is already there and unused and it is an on/off switch (rather than a momentary switch). The standard part number is 10401243 and the deluxe part number is 10273879 - I have no idea what the difference is but either will fit your dash. Unfortunately, both have long been discontinued. You might be able to find NOS (New Old Stock) by searching the internet. ebay is your best bet... they have vendors selling used switches for $20 or less and one vendor is selling new deluxe switches there (just search for 10273879) for $43.
You only have to cut and splice one of the two wires to connect to your switch. It's a circuit which requires both the feed and return wires to function so having either wire interrupted is enough to disable the circuit and cause VATS to prevent starting.
The easiest and most effective disguised switch for a Camaro is a second fog light switch. The dash opening is already there and unused and it is an on/off switch (rather than a momentary switch). The standard part number is 10401243 and the deluxe part number is 10273879 - I have no idea what the difference is but either will fit your dash. Unfortunately, both have long been discontinued. You might be able to find NOS (New Old Stock) by searching the internet. ebay is your best bet... they have vendors selling used switches for $20 or less and one vendor is selling new deluxe switches there (just search for 10273879) for $43.
