Kill switch, 1997 k1500 pickup

[RichLo]

Wire in one of these buttons on the dash and when its pressed or released (your choice) it will light up a bunch of shift lights all over the inside of the cab when they turn the key to ignition, you can tie in the horns for good measure too if you want...

You could also wire in a stereo capacitor so if they try cycling it the lights and horns will stay on long enough for them to run away.

It would make for a good party trick too if you dare your friends to try pushing it while driving.

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[Road Trip]

Also my reason for asking about cutting the ECM-I fuse: looking at the 5.7l wiring below (a bit different to the 7.4l schematic earlier in the thread) and considering an injector killswitch, it seems to show that you need to put the switch over a total of four wires after S161 to kill all the injectors, unless you cut the PNK wire going into S161, and if you do that it kills the VCM ignition feed anyway?

Greetings solaralexx,

Welcome to the GMT400 forum!

To answer your question, the fanout from splice S161 will allow you to implement a kill switch
that will disable fuel delivery at multiple levels. All the starter noise you could want yet
no fuel delivery plus no spark either. (!)

Of course, in order to take advantage of this fanout, you will need to insert your kill switch
in series in between the 20 Amp "ECM 1" fuse and the splice. This fuse is located in the
Underhood Fuse Block:

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I went to the '97 FSM and scanned it for all instances of the occurrence of 'S161'. (There were 20.) I've attached the most relevant pages below:

* 1) The 1st attachment shows the power sent to the 8 injectors. In normal operation, with the key on +12v power is constantly
applied, and the VCM grounds the fuel injector(s) sequentially in the firing order so that electrical current can flow/fuel to spray.
Removing power from S161 disables all fuel injector operation.

* 2) The 2nd attachment shows S161 feeding power to the CKP, Coil, and Ignition Control Module. Without the signals from
the Crankshaft Position sensor, no fuel injection triggers from the VCM will be sent. Also, there's no power to the
Ignition Control Module and Coil, so yet another layer of no start due to no sparks delivered to the spark plugs.

* 3) The 3rd attachment shows S161 feeding power to the VCM.
EDIT: Note that the "Hot at all times" power on the far left of the page is
undisturbed, so the long term trims and emissions monitors will continue
to work properly across driving cycles.

*4) The 4th attachment is where the physical location of S161 is described.

****

If it was me, I would intercept the wire from the ECM 1 fuse to S161 in the middle of the run, and
I'd go to the trouble to use the same color code wire (courtesy of a Treasure Yard donor) in order to
make the addition look as absolutely factory as possible. My '99 C2500 also did not come with air bags,
but as noted in another thread the air bag/no air bag steering wheels look almost identical. (minus a small logo)
So again Skylark's idea to use a factory air bag switch is perfect, especially with being able to remove the key
at both switch positions.

****

Disabling just the CKP power would prevent starting due to missing reference pulses for Ignition and also no fuel injector pulses.
Disabling just the Ignition Control Module would prevent starting.
Disabling just the Coil would prevent any starting due to missing high voltage spark generation.
Disabling just the power to the fuel injectors would prevent any fuel delivery.
Disabling just the VCM power prevents engine operation. And also won't drive the fuel pump relay.

But a kill switch in series between the ECM 1 fuse and S161 disables all of the above.

But the starter will crank. Fruitlessly. But it will crank. :0)

And in this thread we've given the GMT400 community not one but 2 different ways to implement a kill switch.
The first is no starter cranking. And the second allows cranking, but no engine firing. Use whichever one best
matches the desired behavior you want your GMT400 to display when a joyrider or thief tries to take it.

EDIT: If you don't get to implement the kill switch right away but suddenly have to leave your GMT400 behind in
a stolen vehicle hot spot (think airport parking lot due to family emergency or no-notice business trip) then
consider pulling the fuse and taking it with you.

Know which fuse(s) are the ones to pull. For you road trip types, bonus points for pulling these fuses
(one at a time) in the comfort of your own driveway and familiarizing yourself with the resulting engine bay behavior.
And which one causes the SES light to disappear. This may prove valuable for yourself or when you are in Good
Samaritan mode down the road. :0)

Hope this proves helpful.

Cheers --

 

[solaralexx]

Greetings solaralexx,

Welcome to the GMT400 forum!

To answer your question, the fanout from splice S161 will allow you to implement a kill switch
that will disable fuel delivery at multiple levels. All the starter noise you could want yet
no fuel delivery plus no spark either. (!)

Of course, in order to take advantage of this fanout, you will need to insert your kill switch
in series in between the 20 Amp "ECM 1" fuse and the splice. This fuse is located in the
Underhood Fuse Block:

You must be registered for see images attach

I went to the '97 FSM and scanned it for all instances of the occurrence of 'S161'. (There were 20.) I've attached the most relevant pages below:

* 1) The 1st attachment shows the power sent to the 8 injectors. In normal operation, with the key on +12v power is constantly
applied, and the VCM grounds the fuel injector(s) sequentially in the firing order so that electrical current can flow/fuel to spray.
Removing power from S161 disables all fuel injector operation.

* 2) The 2nd attachment shows S161 feeding power to the CKP, Coil, and Ignition Control Module. Without the signals from
the Crankshaft Position sensor, no fuel injection triggers from the VCM will be sent. Also, there's no power to the
Ignition Control Module and Coil, so yet another layer of no start due to no sparks delivered to the spark plugs.

* 3) The 3rd attachment shows S161 feeding power to the VCM.
EDIT: Note that the "Hot at all times" power on the far left of the page is
undisturbed, so the long term trims and emissions monitors will continue
work properly across driving cycles.

*4) The 4th attachment is where the physical location of S161 is described.

****

If it was me, I would intercept the wire from the ECM 1 fuse to S161 in the middle of the run, and
I'd go to the trouble to use the same color code wire (courtesy of a Treasure Yard donor) in order to
make the addition look as absolutely factory as possible. My '99 C2500 also did not come with air bags,
but as noted in another thread the air bag/no air bag steering wheels look almost identical. (minus a small logo)
So again Skylark's idea to use a factory air bag switch is perfect, especially with being able to remove the key
at both switch positions.

****

Disabling just the CKP power would prevent starting due to missing reference pulses for Ignition and also no fuel injector pulses.
Disabling just the Ignition Control Module would prevent starting.
Disabling just the Coil would prevent any starting due to missing high voltage spark generation.
Disabling just the power to the fuel injectors would prevent any fuel delivery.
Disabling just the VCM power prevents engine operation. And also won't drive the fuel pump relay.

But a kill switch in series between the ECM 1 fuse and S161 disables all of the above.

But the starter will crank. Fruitlessly. But it will crank. :0)

And in this thread we've given the GMT400 community not one but 2 different ways to implement a kill switch.
The first is no starter cranking. And the second allows cranking, but no engine firing.

Hope this proves helpful.

Cheers --

Thanks for the welcome, and for this awesome writeup!!

Will try this out when I fly back after easter

 

[618 Syndicate]

If I were to define a casual thief as someone working at the Raising Arizona level, I actually think that a
completely silent starter would make them immediately curious about a kill switch, and in response they
would start rooting around to find/disable it. (ie: They don't have control over the situation, and are
motivated to regain it.)

With Skylark's approach, the vehicle has responded with the engine turning over...but it won't start?
First, they are now making noise cranking the engine over. And the longer this goes on the more curious
the situation becomes.

And second, they may decide that instead of a desirable vehicle being denied them by a kill switch
(motivational) instead they make the snap judgement that the truck is a non-starting piece of cr@p and
should be abandoned. (ie: They are in control of the situation, and they decide to bail on a piece of junk.)

Just trying to take full advantage of human nature.




The all or nothing approach ignores the underlying mathematics of living. And to me that attitude
sounds a whole lot like what the Toronto Police recently told their residents:

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(credit: Watch this video here)


So for me the concept that I give myself the OK to do nothing to prevent loss because there isn't a failsafe solution
just doesn't add up. Maybe the ratio of clowns to pros used to be a 10:1 ratio. So a well thought out kill switch would
be a 90% solution. But given the way things are devolving, the numbers of intelligent pro thiefs with a tow truck may
remain the same, but the number of clowns may increase a large amount? Now, due to the increasing # of thefts,
the kill switch may become a 95-98% solution?

Another perspective on this problem is the question of what kind of environment is the truck being used/parked?

I recently read an interesting article in the Wall Street Journal where they were sharing the statistics of car theft
in 2021 on a state by state basis. Here's an excerpt of the report - note the CA numbers:

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...

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(credit: Read WSJ car theft article here: Jerks on Parade)

Note: The 'theft rate' columns are where they take the number of thefts per number of people living there,
so this helps adjust for population differences. According to the insurance companies, if I lived in a Cali metro
area I am almost 12.5 times as likely to lose the chore truck to theft as I would in metro NH. (A little less bad in Cali
once the rural areas are included -- only ~7.5 times as likely to get stolen vs NH.)

****

For me, the today takeaway is that I'm in the process of moving out of NY.

The chance of moving the chore truck to Toronto & leaving the keys on the front porch? -0-

The chance of moving the chore truck to Cali w/no kill switch and joining that party already in progress? -0-

The chance of moving to NH, adding a camouflaged kill switch, and thereby maximizing the odds of keeping
the chore truck safely in my cheap fleet? 100%

Just being cautious. I'm not here to help people help themselves to my vehicle.

We're defining casual and professional thieves differently. For me the casual thief is a joyrider, or some kid or petty criminal who's looking for a thrill or a quick buck.
The professional is likely stealing to order, or knows what brings top dollar for stripped parts.
It's also a stretch of credulity to leave keys for a thief, obviously I wouldn't help someone steal my shìt. I'm also very aware that if someone wants it, they'll get it, and no property I own is worth the life of me, or anyone I love. Things can be replaced, that's why I have insurance.

 

[Road Trip]

Wire in one of these buttons on the dash and when its pressed or released (your choice) it will light up a bunch of shift lights all over the inside of the cab when they turn the key to ignition, you can tie in the horns for good measure too if you want...

You could also wire in a stereo capacitor so if they try cycling it the lights and horns will stay on long enough for them to run away.

It would make for a good party trick too if you dare your friends to try pushing it while driving.

You must be registered for see images attach

You must be registered for see images attach

RichLo,

Obviously we think alike. *If* I ever get another garage/workshop, it will absolutely need to have a lot of headroom in the rafters.

Why? Because I want a pair of these lurking in the shadows above the workspace:

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Primary use: Ability to listen to clean music over the noise floor created by blast cab or flow bench, level-shifting the whole mess
to a comfortable level via Hi-Fi earplugs. (Like these) (Note: Already doing this on a much smaller scale, works!)

Security use: Upon confirmation of alert from motion detection/security camera setup, play a couple of samples from
this video at Concert-level high-fidelity SPL. Followed immediately by Rage Against The Machine's Pistol Grip Pump,
starting right at the 0:10 mark at full volume. (Security conscious ditty)

Sudden loud sounds are disorienting, especially when perps prefer a quiet, solo stealing session. My sincere
hope is that they would take the hint from the lyrics & vacate the premises.

I'm a happy-go-lucky dude in real life, so think of the above as a high tech "Shoo, Shoo" communique.

For I agree with 618 Syndicate. Raised on the concept of a measured response, it's always best to simply disorient/Deconflict
whenever the choice exists.

:0)

 

[elplatano]

Anyone have experience/opinions on the wireless/remote control relays? To avoid having a switch?

Im looking into the mobilistics version as we speak. Spoke with the owner Jimmie and their relay replacement has 4 pins but our truck has 5. its my understanding that the 5th pin is a redundancy circuit to give power from oil pressure sensor in case of failure, but I asked the forum for some consensus.

Will update!