Kill switch DIY sticky?

[Smokeyyank]

I'll preface all this with electrical stuff isn't my strength so easier the better. I'm looking to install a simple but effective kill switch. Looked through some old threads and seems there are several ways. Wondering if there is sticky somewhere or what's the favorite option for accomplishing this? It would be on a 88. Seems the fuel cut off is a fairly easy one and what I'm leaning towards. Bonus points if there is a way to connect an air horn/siren that would be triggered. 

[AZJeff]

I have a center console in my MJ, and my kill switch is located inside the console, hidden inside the storage compartment in the console.   

 

Adding the siren/horn feature would require a method to detect unwanted attempts to start the vehicle, so that once starting is attempted while the pump is dead, it would trigger the horn.   That's not a simple plug and play, since now you need an added sensor and circuit to indicate when the starter is engaged with the fuel pump power is off, and then trigger the horn in response.  (It would also have to shut the horn OFF after you turn the fuel pump back on, for those times when you forget to turn the pump on before cranking.   Ask me how I known. )

[Pete M]

if you want an alarm, just buy a car alarm and install it.  

 

if you are looking for a kill switch, I prefer to wire it in (with a relay) to the pump resistor wire so the truck starts but dies after each attempt making it appear that it's just an old piece of crap rather than a protected truck where the thief just needs to find the kill switch.  this is hypothetically speaking of course.  I've got no idea of the thought process inside a thief's head. 

[Smokeyyank]

1 hour ago, AZJeff said:

That's not a simple plug and play, since now you need an added sensor and circuit to indicate when the starter is engaged with the fuel pump power is off, and then trigger the horn in response.

That's what I was thinking. Wasn't sure if it would be a simple add on or require more. Thanks! 

 

25 minutes ago, Pete M said:

I prefer to wire it in (with a relay) to the pump resistor wire so the truck starts but dies after each attempt

 

That's what I was leaning towards. My neighbor a few doors down had their XJ swiped last year. Was a few junkies that used it to go on a robbery spree and god only knows what else. Just want something to at least not make it easy if it was to ever happen. Is there a good writeup with some info on doing that? 

[eaglescout526]

I think your best bet is to get some ideas and do one of them. Not to think like a thief but if you think like most, they’re dumb and want quick and easy. If they’re smart and they know what they’re stealing, a Google search of “Comanche kill switch” could easily point them to here about a write up. 

[Pete M]

it's not any different than wiring a relay.   lighting relay kits are all over ebay and amazon.  look up a relay diagram and then extend the activate wires to your switch and the power transfer wires to the wires at the fuel resistor.

[AZJeff]

Your average thief is not going to hang around your vehicle for long periods of time trying to figure out why the vehicle won't start.   They want to smash a window, overpower the ignition lock, and be gone with the Jeep as quickly as possible.  The longer they hang around a vehicle with a jacked up steering column and/or a broken window, the more attention it would attract.

 

That said, I think HIDING the kill switch from plain sight does as much to defeat thieves as the actual kill switch itself.   Putting an unmarked switch on the dash isn't nearly as effective as placing one in a location that a thief either cannot see, or would not think to look.

[Ωhm]

5 hours ago, Smokeyyank said:

I'm looking to install a simple but effective kill switch

 

Take the Fuel Pump Feed wire and using a SPDT (on-on) switch, connect it to the vehicle Horn wire at the Horn Relay. Both wires are under the dash near the parking brake. When set and IGN SW is in the CRANK position, horns will blow. Horns will also blow, but not as loud (4.0L only) for 2-3 seconds when IGN SW is in the ON position. Vehicle will not START since Fuel Pump is OFF and has no power feed.

[jpnjake]

If your thinking about installing an air horn it’s not hard at all, here’s the pictures from my install, I even have it all connected to a factory switch (XJ washer, up is compressor, down (momentary) is horn), and you could add a way to activate it with a kill switch if you wanted. The horn is installed in the front crossmember, and the compressor and tank are mounted to the coolant bottle bracket as I converted to open cooling 

 

Personally when I go somewhere I’m worried about theft I pull my coil wire and fuel pump balist resistor wire, but I understand the appeal of a killswitch 

 

[eaglescout526]

Orrrrr you yank the fuel pump relay.

[jdog]

7 hours ago, AZJeff said:

I have a center console in my MJ, and my kill switch is located inside the console, hidden inside the storage compartment in the console.   

 

Adding the siren/horn feature would require a method to detect unwanted attempts to start the vehicle, so that once starting is attempted while the pump is dead, it would trigger the horn.   That's not a simple plug and play, since now you need an added sensor and circuit to indicate when the starter is engaged with the fuel pump power is off, and then trigger the horn in response.  (It would also have to shut the horn OFF after you turn the fuel pump back on, for those times when you forget to turn the pump on before cranking.   Ask me how I known. )

You could rig it up with a relay

[Eagle]

A kill switch in the fuel pump circuit doesn't need a relay.  It obviously won't hurt to install one, but just based on the gauge of the wire, any decent toggle switch should be able to handle the current directly.

 

[Smokeyyank]

3 hours ago, Ωhm said:

 

Take the Fuel Pump Feed wire and using a SPDT (on-on) switch, connect it to the vehicle Horn wire at the Horn Relay. Both wires are under the dash near the parking brake. When set and IGN SW is in the CRANK position, horns will blow. Horns will also blow, but not as loud (4.0L only) for 2-3 seconds when IGN SW is in the ON position. Vehicle will not START since Fuel Pump is OFF and has no power feed.

 

Appreciate the info. This is pretty much what I'm looking for. Really just want a horn to go off as an alert. 

[fiatslug87]

https://www.mobilistics.com/nostart-remote-controlled-intelligent-relay-w-remote-starter-fuel-pump-immobilizer/

[Smokeyyank]

1 minute ago, fiatslug87 said:

https://www.mobilistics.com/nostart-remote-controlled-intelligent-relay-w-remote-starter-fuel-pump-immobilizer/

 

Cool idea, my worry would be the remote not working or battery pooing out. 

 

[fiatslug87]

Battery is replaceable and just carry a regular relay just in case.

[Smokeyyank]

1 hour ago, fiatslug87 said:

Battery is replaceable and just carry a regular relay just in case.

 

Good call on the spare relay. Might be the way to go. Thanks for the info. 

[Armyvet25]

I usually wire one to two kills tied into one switch, distributor hot from ignition(no spark) and ignition to starter solenoid(no crank) and I use a relay with inline fuse, may be overkill with the relay and fuse but protects the circuit from any accidental shorts. And don't forget to mount the toggle switch on the dash labeled "kill switch" which actually triggers an alarm that can't be shut of with merely switching it back off, thieves are so stupid!

Don't leave new wires underhood exposed, run them into an existing or new wire loom so not obvious.

[Eagle]

On 2/10/2023 at 5:28 PM, Ωhm said:

 

Take the Fuel Pump Feed wire and using a SPDT (on-on) switch, connect it to the vehicle Horn wire at the Horn Relay. Both wires are under the dash near the parking brake. When set and IGN SW is in the CRANK position, horns will blow. Horns will also blow, but not as loud (4.0L only) for 2-3 seconds when IGN SW is in the ON position. Vehicle will not START since Fuel Pump is OFF and has no power feed.

 

This is brilliant!

[coheed]

My "kill switch" isn't really a kill switch. I cut into the signal wire for the starter relay and put an on/off switch on it. So if it's not on the starter won't turn over. Quick nondescript anti-theft measure, and no electric fuel pump for me so that wasn't an option. 

 

Also a very obvious lighted security cam pointed at the driveway is a deterrent.

[gogmorgo]

21 minutes ago, coheed said:

My "kill switch" isn't really a kill switch. I cut into the signal wire for the starter relay and put an on/off switch on it. So if it's not on the starter won't turn over. Quick nondescript anti-theft measure, and no electric fuel pump for me so that wasn't an option. 

 

Also a very obvious lighted security cam pointed at the driveway is a deterrent.

If it were me and I hit the key and nothing happened, first thing I’d try is shorting the solenoid. This would completely bypass your kill switch, and it’s easy enough to do just by rolling underneath. Would a thief do it? Maybe, maybe not. But it would be better to pull power from the ignition system or something that actively prevents the engine from running.

[Ωhm]

@Eagle   Thank you for your kind words. I did try to keep it simple, plus I went for the bonus point.

[coheed]

14 hours ago, gogmorgo said:

If it were me and I hit the key and nothing happened, first thing I’d try is shorting the solenoid. This would completely bypass your kill switch, and it’s easy enough to do just by rolling underneath. Would a thief do it? Maybe, maybe not. But it would be better to pull power from the ignition system or something that actively prevents the engine from running.

I guess it's good you're not trying to steal my truck then . I never said it was fool proof. I was just offering the small thing I did to my truck.

 

A few years back I saw an interview with a professional motorcycle thief and the gist of the advice he had to give was make your stuff less convenient than your neighbors. The quote that stuck out was "I'd steal the sportster on the street before the Ducati in the garage." My 37 year old truck that's 6 different colors, in front of a camera, that doesn't start first try is much less desirable that my neighbors unsecured, unsurveilled stuff.

[Gojira94]

On 2/10/2023 at 8:57 PM, Smokeyyank said:

Appreciate the info. This is pretty much what I'm looking for. Really just want a horn to go off as an alert.

 

One idea to throw out there - SPDT switch; position 1 is power to fuel. Position 2 it completes a supplemental circuit to the (air) horn, with an open triggered closed on the ignition switch or some other circuit the thief will activate by trying to start it.

 

EDIT: I think I stole Ohm's idea (great use of the built in behavior of the ignition switch and start sequence) by way of incomplete reading on my part... I think his idea still works if hotwired at the switch wiring on the column. My idea was thinking hide the switch and second circuit to a second horn somewhere underneath and let the ignition switch close the circuit to the (second) horn once armed at the switch with fuel turned off.

[zomeizter]

All for y'all to install a kill switch on your hoopty, but don't give no details on how/where it is...