Identifying Starter Motor Signal Wire for Kill Switch

[RustyShackleford2022]

First post! I custom-ordered a 2022 Wrangler Rubicon and I love it to death. It has been quite a learning curve though trying to understand the wiring compared to my 2007 mustang.

The impetus for this post is that I live in an apartment complex where there have been a lot of break-ins and car thefts. I would like to install a kill switch connected to the starter motor system. I would like the kill switch to operate such that you have to hold it to the ON position while the car is starting (and the computer is continuing to signal the starter motor to crank) and then you can let go (back to OFF) once the car is running. The reason for this is that I want to avoid a traditional on/off kill switch in the ignition system setup where I have to remember to re-engage it every time I leave the car. If modern cars work like my 2007 mustang did, the command/signal to the starter to run would only be needed while the engine is running, so it would be okay for the wire carrying that command to be disconnected once the car is running.

Based on what I am seeing, my first guess was that I would put my switch on the BN/BG wire coming out of the left side of the Body Control Module in the picture below. I have located the BCM module and the wire but now I am having my doubts. From the diagram it looks like this wire sends the signal to the Stop/Start Relay which also is connected to the relay for the starter solenoid. However, if you click the link above you can see there are quite a few other systems also connected to this. This makes me pretty sure that it would not be good, or maybe even possible, to have this wire in a setup where it is OFF by default while the engine is running as the other systems would be disconnected when the switch goes back to off after the engine starts.

My question is, if that is not the signal wire that tells the starter motor to run, which is it? Surely there is an isolated wire that does not connect to the other systems with the sole purpose of sending the signal to run the starter motor?

My other thought would be to tap into one of the YE/GY wires immediately to the left of the Body Control Module in the linked above diagram. However, I would prefer not to, as I think those are the actual power wires to run the starter, which would be high amperage. I would rather tap into the low voltage/low amperage signal wire if that is an option.

Any advice or thoughts would be much appreciated.

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[kaptkaos]

Heres my advice, call Ravelco and have them come out and do the full install. Its the best $700 I spent. Clean, professional install and it has yet to be defeated without a tow truck.

 

[RustyShackleford2022]

Heres my advice, call Ravelco and have them come out and do the full install. Its the best $700 I spent. Clean, professional install and it has yet to be defeated without a tow truck.

I know a lot of people use those, I would rather save money and install my own kill switch though.

 

[Willys41]

I agree
Ravelco
I was skeptical at first and when the installer arrived I had a slue of question and all where answered to my satisfaction
He dove deep into the wiring lumen and he showed me what he did
They use a 16 pin plug that has 100k different combination put not all wires are being used and all wires are black some being hooked to ground. So trying to jump all the correct wires and not jumping one to ground and blowing a fuse . Good luck

https://www.nohotwire.com/?utm_sour...7fv9ZTAostPyRwK7gNXUJwLtnrZ9ZSOhoCo00QAvD_BwE

 

[swampflyer]

Have an appointment Wednesday for the ravelco install. He said it will take about 3 hrs. after he arrives. This will be interesting. It is a little expensive but pay once cry once. Since this is probably my last jeep I would like to try and keep it. With the cost of these vehicles constantly increasing its a worth while investment.

 

[dstevens]

You don't want to tap into the F2 wire that runs to the starter - current is going to do bad things to the momentary switch. Also you never know if the power distribution center is checking the path to the starter. If the PDM relays are solid state then the wiring diagram shows what the PDM would look like with discrete components rather than what it actually is.

If you have a MT then the clutch interlock would be a good choice. Put the momentary behind a plastic panel so you have to press on the panel rather than have the button zip tied under the dash.

For an AT perhaps H8 would work.

However, I don't see any way ESS is going to be happy with the starter disconnected.

 

[kaptkaos]

The Ravelco was worth every penny. Zero regrets.

 

[RustyShackleford2022]

You don't want to tap into the F2 wire that runs to the starter - current is going to do bad things to the momentary switch. Also you never know if the power distribution center is checking the path to the starter. If the PDM relays are solid state then the wiring diagram shows what the PDM would look like with discrete components rather than what it actually is.

If you have a MT then the clutch interlock would be a good choice. Put the momentary behind a plastic panel so you have to press on the panel rather than have the button zip tied under the dash.

For an AT perhaps H8 would work.

However, I don't see any way ESS is going to be happy with the starter disconnected.

Really good point about the ESS needing the starter to be connected at all times, I forgot about the silly start/stop feature.

I have an automatic. Okay I will think about this some more. Guess starter is out of the question though.

Lot of Ravelco support hahah is this forum sponsored by the company jkjk.

I grew up fixing everything on my cars myself and maybe it’s a stupid pride thing but paying $700 for them to install something that can probably be manufactured for $10 seems silly. Even assuming labor to install is $100 an hour still seems crazy. Maybe by the end of this i’ll end up getting one but for now still looking at diy options.

 

[dstevens]

Things get a lot easy if you go to a switch rather than a momentary. Anything on the coil side of a relay would work. Ravelco only intercepts two wires (which of course are secret) but I'd guess the coil side of a relay.

 

[Willys41]

I agree
I have been doing all my own work on all my cars and trucks sense I was 16
Put back then no computers key fobs only points and condensers and if you tried to take my car you would get shot
Put today it is out of control. If I try to stop some one or defend my self I go to jail
Less than 5 minutes and your jeep is gone
I will do every thing possible to keep my 85k investment and investing $700 on a Ravelco to keep it is fine with me

 

[Willys41]

Not true
I wont go into details. Put Ravelco is more complected then that

 

[brican]

I don't think anyone answered the original question. Which wire can be used on an ignition kill switch?

 

[Mx5red]

Not sure specifically but I’d pull the starter button and put in a switch. Easy and can use remote start, if so equipped.

Supposedly same harness as Ram. Can either splice in or order harnesses so can take off later.
https://www.ram-trx.com/threads/“plug-and-play”-anti-theft-kill-switch.10323/

 

[PatrickIvan]

I saw a similar thing here the other day:

 

[jpribe]

Have you looked at the wiring for the stop/start switch and/or fuel pump?

I like the idea of ravelco but it's just security through obscurity. There's actually a device out there could decode the ravelco wiring (called an eclipse tester) but those are out of reach for your average thief.

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