Question about adding an ignition kill switch

[dang]

I plan on adding an ignition kill switch to several of my older vehicles but I'd like to do it similar to how a friend did his 2002 years ago. I can't contact him to ask so I thought I'd ask here. He used some kind of momentary push button switch that stayed connected when the power was on but disconnected when power is shut off. I think it's an NVR (No Voltage Release) switch but I'm having trouble finding it for 12v and the right application. It was a very small switch with a red button that was maybe 1/4" in diameter. He mounted it under the driver's seat, so you turned the ignition on, reached down and pressed the button, which felt magnetic, and then started the motor. As soon as you turned the ignition off the switch released and opened the circuit.

Anyone familiar with this type of switch?

Thanks,
Dan

 

[bdigel]

Im not familar with what your talking about about my kill switchs kill the power from the battery , I use a large solenoid for battery cables and it is operated by a toggle switch , it requires a few other steps as well to stop back voltage from the Alt

 

[dang]

Im not familar with what your talking about about my kill switchs kill the power from the battery , I use a large solenoid for battery cables and it is operated by a toggle switch , it requires a few other steps as well to stop back voltage from the Alt

Yeah, a battery cutoff is pretty common but you have to remember to turn it off (disconnect) each time. A momentary switch that stays on with power but off when the power is turned off is guaranteed to always work as an ignition cutoff.

 

[HB Chris]

The easiest is a wire to interrupt the green power wire to the coil.

 

[dang]

The easiest is a wire to interrupt the green power wire to the coil.

That's the plan, but I still need a switch.

 

[HB Chris]

I would use the Orange rear defrost switch as they never work anyway!

 

[dang]

I would use the Orange rear defrost switch as they never work anyway!

I'm looking for a switch that disconnects when power is turned off.

 

[Ohmess]

Looks like you could do this with a pair of relays and a momentary contact switch: https://www.the12volt.com/relays/starter-interrupt-diagrams.asp#psk

 

[coupedegrace]

A buddy of mine put in a RFID immobilizer after his Westphalia was stolen. He got it from an eBay vendor and has been happy with it. I'm not sure of all the details, but I expect it's method of not allowing the motor to run is similar to what Chris mentioned. I do know that if a thief was trying to steal it they would probably assume that it just wouldn't start as opposed to thinking that there was a kill switch somewhere that might get them to start tearing the dash apart looking for it.

I glanced at it on eBay and it looked like a pretty simple solution. I can ask him for details if anyone's interested.

Funny story about the stolen van - this guy is one of those people who sucks up all the luck in the room. He once had a Toyota van stolen and got it back with a like-new, very nice sleeping bag in it. The Westphalia was recovered the same day it was stolen. No real damage to it. The only thing missing was a few Mexican Cokes, a bottle of bourbon and a pair of cheap, backup binoculars. Oh yeah, and in their place was a Specialized Allez bicycle.

The cops told him: "We found your van. It looks like it's in pretty good shape. Your bicycle is still in it."
My buddy: "I don't have a bicycle."
Cops: "Well you do now."

 

[dang]

I remember a little more about it now. He had a push button switch but it didn't have a spring on it. The button was loose, but it was mounted upside down under the seat and when the ignition was powered on you depressed the button and it stayed connected. It had a magnetic feel to it when it connected, which would make sense I guess. As soon as the ignition power was turned off by the key the button would fall down opening the circuit.

 

[dang]

Looks like you could do this with a pair of relays and a momentary contact switch: https://www.the12volt.com/relays/starter-interrupt-diagrams.asp#psk

I think my friend went the simple way and found a switch that worked like how I described above, but using one of those diagrams you posted might work good too. I'll have to spend some time understanding it. Thanks.

EDIT: I think this one will work.

This is a stand alone starter kill. It does not rely on an alarm or keyless entry for it to work, only a simple momentary contact switch (normally open) to deactivate it. Every time the ignition is turned off, continuity is broken on the starter feed wire. To disable (or start), turn ignition on, then press the hidden switch, then start as normal.