Electrical Guru? Starter Relay Killswitch Mod.

I'm looking into getting a bit more security for running doorless with the warm weather ahead.

I've heard and seen a few running the Starter Relay kill switch modification. Does anyone have the ability to elaborate on how to do this or have a writeup anywhere? All i've found is this http://www.the12volt.com/relays/page2.asp#sk2 which is very useful, though i'm not fully understanding the diagrams.

All you have to do is interrupt the small wire for the starter solenoid - looks like Haynes has it listed as the brown wire, though they don't specify a year and I don't feel like paging through the FSMs at the moment. You could also interrupt the yellow wire to the starter relay. Make sure you use a waterproof switch!

All this does is make it so the Jeep won't turn over, if you really want to do a good job, put a switch or switch-driven relay on the power rail for the fuel injectors - on the 91 and later models, it seems it's a dark green wire with an orange stripe. This will confuse any thief a lot, as the engine will turn over but simply won't start. You could combine this with a hack to make the fuel gauge show as completely empty when the killswitch is engaged and they might even leave you some free gas while trying to steal it, or will get frustrated and move to the next target.

I agree that all looks complicated if you don't understand relays. It is simple though and there is a couple of ways to do it. One would be to just put a switch in the ground wire off your current starter relay. It would act like a neutral safety switch that had gone bad. The other is to put a solenoid in the positive battery cable with a heavy duty switch to operate it.

Well recently i'm finding out this is commonly avoided because of how much voltage is being carried through this.

Is it better off using this same idea with not the starter but with the fuel pump or the ignition?

What about a killswitch to the battery?

Wouldn't the battery be the same concern as the starter, carrying a lot of voltage?

It's not the voltage- it's the high amperage.

Google a bit- this is nothing new, and not specific to Jeeps (although the exact wires you'll need to tap into will be). There's a wealth of information out there regarding relays, switches, wiring, and how to modify DC circuits if you look for it.

Maybe just run an interrupt wire from the NSS?

hubs97xj said:

It's not the voltage- it's the high amperage.

Google a bit- this is nothing new, and not specific to Jeeps (although the exact wires you'll need to tap into will be). There's a wealth of information out there regarding relays, switches, wiring, and how to modify DC circuits if you look for it.

Click to expand...

I'm well aware this is not Jeep specific, though it is something I'd like to modify my rig with, and I have little experience with electrical work. Some are more willing than others to give advice unfortunately. I hope not all your posts are as worthless as this one was hubs97xj :yelclap:

I did use the search feature here and it came up with little to nothing on the subject, let alone Google i wasn't too specific with because i was very vague with knowledge of what I'm looking for.

It looks like i'll just go with a battery cut kill switch, seems easiest with little information needed...

i run an nss by pass it as so simple but its not 100% theft proof. its way easy. i would suggest talking to your local stereo/alarm shop you can get a ignition kill sys for cheap.

Johnnie Walker said:

Maybe just run an interrupt wire from the NSS?

Click to expand...

by the battery there should be a starter solenoid thing. below the main power terminal will be a green wire with a large plastic squarish housing. if that comes off your starter doesnt work. instead of messing with the heavy duty power wires you can use a relay to cut power to that wire. i would use the normally open relay which is your standard relay

cut your green wire 87 and 30 are your green wire 86 and 85 are your hidden 12 volt switch wire

Jeep89JV said:

Well recently i'm finding out this is commonly avoided because of how much voltage is being carried through this.

Is it better off using this same idea with not the starter but with the fuel pump or the ignition?

Click to expand...

Don't you mean amperage??

/EE :twak:

Search. It's been discussed. Here's one to get you started.

http://www.naxja.org/forum/showthread.php?t=986098&highlight=kill+switch

Fuel pump kill switch is about as easy as it gets. Under the rear passenger seat on the driver side two wires go through a rubber grommet in the floor. This is fuel pump power and ground. Use a test light to identify the power wire. Cut the wire. (I imagine this would work just as well cutting the ground wire, but have only seen it done with the hot lead). Run two wires from wherever you are putting your kill switch, under the driver lower door trim along the wire loom, ultimately ending at your freshly snipped fuel pump wires. Solder the two new wires to each of the snipped fuel pump wires, and connect the wires to your switch on the other end. (if you electrical tape the new wires to the existing wire loom, you can hardly tell they aren't stock). You now have an interrupter that prevents the fuel pump from charging. If a thief tries to crank the engine, he might get a sputter, but that's it, and since the switch could be anywhere, too much work to track down, they move on to the Ford Explorer down the street...(not the smartest second choice, but if they were smart, they wouldn't be thieves.)

And of course it would be extremely helpful for us if you'd post the pertinent info regarding the details of your rig. The fuel pump kill switch it by far the most popular and discussed method on here. However I wouldn't put the switch under the rear seat I'd pull back the kick panel on the drivers side and splice into the wires running from there so the switch could be mounted and hidden under the dash by your knees.

Good deal i appreciate all the responses here guys, also appreciate the link supplied with more discussion on this. Not sure why i missed that when i tried but i am glad i've gotten information needed.

just another bit of info, i put a hidden switch that interrupted the fuel pump. this is easy because its just 1 pos. wire that runs right through the kicker panel.
pop off the panel, put switch in, done

EDIT: beaten by shanesaw