Kill switch, 1997 k1500 pickup

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skylark

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According to this wiring diagram your proposed kill switch would be very effective. And I really like
the way you are hiding the enable in plain sight, yet camouflaging it by the visual association with the
air bag system.

So the engine cranks over, but no joy. I'm guessing that there wouldn't be the SES light, which would
be a good reminder for you, but the J*ck@ss trying to steal it would never notice. The stealth aspect
is a nice touch. Good stuff.
No ses light. The PCM would be unaware of the injectors not firing. It simply cranks but doesn't start. Most likely a thief won't continue on because it isn't easy and it made noise. A starter disable means that a thief knows that there is a power issue that they can bypass with a screwdriver and they have been undetected.
 

someotherguy

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No ses light. The PCM would be unaware of the injectors not firing. It simply cranks but doesn't start. Most likely a thief won't continue on because it isn't easy and it made noise. A starter disable means that a thief knows that there is a power issue that they can bypass with a screwdriver and they have been undetected.
Isn't the passenger airbag switch normally "closed" though? As in, enabled? To turn it off would be an unusual position for that switch for most people, IMO. Something to consider in your stealth operation. I dig it, though.

Richard
 

skylark

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Isn't the passenger airbag switch normally "closed" though? As in, enabled? To turn it off would be an unusual position for that switch for most people, IMO. Something to consider in your stealth operation. I dig it, though.

Richard
I haven't dug into it to figure that out. My plan was based on my S10 where the key can be removed from the switch in either position.
 

skylark

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I should also mention that when I do this it'll be in our 2000 3500hd which doesn't even have an airbag. I plan to install the factory switch into the dash and tie it into the fuel solenoid. All wires will be hidden in the factory harness and loom. It'll just be another broken 6.5.
 

skylark

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Also keep in mind that anything you do is only going to deter a casual thief. If a professional wants your vehicle they're gonna get it, I don't care what you do to try and stop them.
Agreed. That is why I don't like a starter disable. It is too easy to figure out.
 

618 Syndicate

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Agreed. That is why I don't like a starter disable. It is too easy to figure out.
That's exactly why I like them. When it doesn't start the casual thief moves on to the next vehicle, they don't waste time trying to figure it out. The professional is gonna take it anyway, so there's no point in trying to stop them.
 

solaralexx

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Some great info here, I am planning a killswitch too. To summarize what I have learned from this thread as a newbie:

starter kill on control circuit:
- can be implemented inside the cabin by I/P fuse 8
- low current, reliable
- starter control can be easily bypassed by giving 12V to starter relay pin 87
- doesn't make a noise, so thief can take their time to figure it out

starter kill on start solonoid circuit (PPL wire):
- more difficult to find and hotwire when placed under fuse block
- higher current, maybe less reliable
- also doesn't make a noise

fuel pump kill:
- fuel pump must be killed via GRY wire below oil pressure switch and S100 (see page 6E-516 of 1997 SM for 5.7L)
- starter makes noise
- can still be driven until fuel lines are empty

coil kill:
- starter makes noise
- engine can potentially flood if thief is persistent

injector kill:
(see page 6E-520 of 1997 SM for 5.7L)
- starter makes noise

I am wondering: is also possible to put a killswitch over the ECM-I fuse which goes to the VCM ignition feed? Drawbacks of this?
 

Road Trip

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That's exactly why I like them. When it doesn't start the casual thief moves on to the next vehicle, they don't waste time trying to figure it out.

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 professional is gonna take it anyway, so there's no point in trying to stop them.

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.
 
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solaralexx

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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?
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