Where to find switched 12 volts that doesn’t drop during crank?

[Green717]

I installed a relay with magnetic sensor kill switch based on a schematic found here. I had to modify it a little from the Jeep example, specifically the power source. After bench testing the circuit successfully, I installed it in the car and connected the relay coil to switched 12 volts on the cigar harness. Unfortunately I overlooked the behavior of accessory switched 12 volts.
Push the start button once, accessories turn on. Swipe the magnet, relay energizes. Ready to start. Nope, push the start button again to crank and accessory 12 volts drop out, the relay coil shuts off, re-enabling the kill switch.
I need a spot to tap 12 volts that comes on upon first push of button and STAYS ON while the starter is cranking.
I found one vague reference on another forum pointing to a brake circuit which makes no sense to me.
I really like the convenience and stealth of this kill switch and hope someone can point me in the right direction.

 

[BULL]

@Diboblo

 

[Diboblo]

PM on the way...

Bob

 

[Jack_Toepfer]

Brake circuit is interesting. Depending on the purpose of that circuit, it could be the signal that tells it the brakes are on and to continue starting… like a safety switch.

 

[BULL]

Brake circuit is interesting. Depending on the purpose of that circuit, it could be the signal that tells it the brakes are on and to continue starting… like a safety switch.

Brilliant!

; )

 

[Diboblo]

Built this circuit, in my shop. Works great!

Also, after arming, with the initial flyby, subsequent attempts to arm, while armed, leave the relay in its armed state.

I read where some jeepers were installing a lockout switch, because they were afraid of disarming, on rough roads. No need to worry, the design maintains state until power is removed.

Pretty sneaky, sis...

Sent from my SM-G955U using Tapatalk

 

[Stormtrooper1320]

I'm going to have to see if something like this could be made for Fords.

and yes....I know....it's a Ford.....and no one steals those....

but MINE is cool

 

[Diboblo]

I'm going to have to see if something like this could be made for Fords.

and yes....I know....it's a Ford.....and no one steals those....

but MINE is cool

I would simply connect it to the fuel pump relay.

It is not Stellantis specific.

Sent from my SM-G955U using Tapatalk

 

[Stormtrooper1320]

I would simply connect it to the fuel pump relay.

It is not Stellantis specific.

Sent from my SM-G955U using Tapatalk

That's my typical Ford interrupt is the fuel pump, been doing that for years. I liked the idea of this magnet gadget.

I got myself a fake OBD2 port. if someone hooks to it, it lets power come through so they think they are onto the real port, but then it doesn't have wires to go anywhere else so their programmer is useless at that point.

I just have to remember to undo it when I go to the dealer

 

[Magnified]

Run 50000 volts through the fake obdii

 

[Stormtrooper1320]

Run 50000 volts through the fake obdii

I'd rather have the vehicle auto lock them in and then dispense a cloud of Ricin.

The cleanup afterward is a bitch though, almost like vacuuming up dry chem fire extinguisher agent.

 

[Green717]

@Diboblo and I are still working on it. Great guy.

50,000 volts, sleeping gas, believe me, it’s crossed my mind. But I worry about that one distracted time when I push the start button and forgot to swipe that magnet.

 

[vortecd]

 

[Green717]

Where to find switched 12 volts that doesn’t drop during crank?

Short answer : It doesn’t exist.

But @Diboblo showed me how to tap into brake light signal to bridge that gap between when switched accessories turn on and car is running.

Many thanks to @Diboblo