Technical Hidden switch - which wire to cut (theft protection)?

[internecik]

Hi! I have a Ducato 2,3 2020 and I want to make a hidden switch to make it harder to steal this car.

I want cut the orange wire supplying the fuel pump, but I checked that when I was driving and my additional immobilizer failed and cut off the power to the fuel pump, the car suddenly turned off (which could be dangerous on the motorway).

What other wire can be cut in this car that will prevent the engine from starting (thief), but will not cause "check engine" errors and the engine will not turn off while driving if this hidden switch fails?

Thank you very much for your valuable advice and diagrams.

 

[the green vanper]

Hello,

Attached two eLearn docs on the diesel engine management system. Might be helpful to understand how the system works and invent which wire could be used for such purpose.

 

[internecik]

On another forum someone advised me to cut the brown-gray wire in the ignition switch harness. Is it a good idea?

 

[Communicator]

Hi! I have a Ducato 2,3 2020 and I want to make a hidden switch to make it harder to steal this car.

I want cut the orange wire supplying the fuel pump, but I checked that when I was driving and my additional immobilizer failed and cut off the power to the fuel pump, the car suddenly turned off (which could be dangerous on the motorway).

What other wire can be cut in this car that will prevent the engine from starting (thief), but will not cause "check engine" errors and the engine will not turn off while driving if this hidden switch fails?

Thank you very much for your valuable advice and diagrams.

@Reg 65 ?

 

[Communicator]

Hi! I have a Ducato 2,3 2020 and I want to make a hidden switch to make it harder to steal this car.

I want cut the orange wire supplying the fuel pump, but I checked that when I was driving and my additional immobilizer failed and cut off the power to the fuel pump, the car suddenly turned off (which could be dangerous on the motorway).

What other wire can be cut in this car that will prevent the engine from starting (thief), but will not cause "check engine" errors and the engine will not turn off while driving if this hidden switch fails?

Thank you very much for your valuable advice and diagrams.

Are you setting the bar too high? Or are you not confident in the quality of your proposed modification? You rely on the ignition switch not to fail while driving, as it would bring you to a sudden stop if it failed.

 

[theoneandonly]

Fuel pump is between seats

 

[Communicator]

Fuel pump is between seatsView attachment 464611

In his initial post, internecik said:

I want cut the orange wire supplying the fuel pump, but I checked that when I was driving and my additional immobilizer failed and cut off the power to the fuel pump, the car suddenly turned off (which could be dangerous on the motorway).

 

[the green vanper]

The tracking systems that are connected to the ignition system cannot switch off the ignition when driving. As far as I know it's a legal requirement in the EU. After it is switched off by the administrator, the vehicle runs as long as the ignition is on. Once off, it cannot be restarted.

I have no idea how exactly this is managed, I know the tracking systems are connected to CAN.

 

[Communicator]

What is required is something that prevents the engine from starting, and leaves no clues. I can think of a possible solution, but it would be more complex to install than a basic switch.

 

[theoneandonly]

I am aware of one person that used this diagram but precisely what he did i dont know and he cant remember and it has since been moved on. When i removed the connector and put ignition on i got a orange warning pherhaps he was prepared to run with a light. Leaves no clues.

 

[Reg 65]

@Reg 65 ?

Only just seen this thread. On the X2/50 and X2/90 I use a secret switch to interrupt one of the 2 thin wires that go from the antenna coil around the ignition switch to the ECU.
When the secret switch is off the ECU can't communicate with the chip in the ignition key, so the padlock symbol on the dashboard panel illuminates and the engine won't start (but it keeps running once started if you turn the secret switch off)

 

[Irgendeiner]

@Reg 65: Disabling the start of the system is the easy part ;-)

My difficult question: What can be done if it does not start with good key inserted because the electronics box "wfs 125f2" is defective?

 

[Irgendeiner]

No answer in sight?
I am scared to leave to Sicilia when thinking about the horror scenario that the defect again occurs while nobody there will know how to remedy it ... :-((

 

[Jakeroyd]

On X250 I interrupted the wire from the ignition switch to the solenoid on the pre-engaged starter motor.
This was wired to the normally closed contacts of a standard 12v relay.
Relay activation is remote via my tracker.
But you could actuate the relay via your added hidden switch instead of the tracker.
My relay is located behind the radio (yes a knowledgeable thief would look here)
If not immobilized and stolen it does not prevent the engine running but once activated it would not start again.
Can provide details if you are interested.

 

[Communicator]

On X250 I interrupted the wire from the ignition switch to the solenoid on the pre-engaged starter motor.
This was wired to the normally closed contacts of a standard 12v relay.
Relay activation is remote via my tracker.
But you could actuate the relay via your added hidden switch instead of the tracker.
My relay is located behind the radio (yes a knowledgeable thief would look here)
If not immobilized and stolen it does not prevent the engine running but once activated it would not start again.
Can provide details if you are interested.

@Jakeroyd I thinkk that Irgendeiner was posting on the wrong thread. Having had some key code failures on his x244, he was concerned that it should fail when on holiday, and leave him stranded. He has started his holiday, and promised to report on his return. His thread may be viewed here.

 

[Jake Royd]

@Jakeroyd I thinkk that Irgendeiner was posting on the wrong thread. Having had some key code failures on his x244, he was concerned that it should fail when on holiday, and leave him stranded. He has started his holiday, and promised to report on his return. His thread may be viewed here.

ok #communicator , thank you.

 

[Reg 65]

On another forum someone advised me to cut the brown-gray wire in the ignition switch harness. Is it a good idea?

Fuel pump is between seatsView attachment 464611

Apologies to Robert56 for carrying using his thread.

I think that IH replaced the original Fiat seat bases with ISRI bases and turntables. The bases are made from heavy gauge guesstimated at 20mm tube which overlaps sideways at the base. This restricts the maximum length of a transverse mounted battery to 306mm, which is subject to confirmation. My XD27 batteries are 302mm long. It may be possible to mount lower height batteries lengthwise, but a special support frame would be required and height then again becomes a consideration. Incidentally the seat and turntable are also hefty items. Both need to be removed to access the battery.

I interrupted the grey/white wire, which is one of the 2 thin wires going from the coil around the ignition switch to the ECU. You can intercept it around the base of the steering column to avoid dismantling the plastic around the steering wheel. You could intercept either and the other thin wire may be brown/white. But I am reluctant to give any wiring colours for the Ducato due to their inconsistency in the colours of wires used. Apparently when the Fiat loom manufacturers run out of one colour they use whatever colour comes to hand!!! Make sure your connections are good because its very low current. But you can use long wires to your secret switch - 4 metres or so in each direction still works fine. If you want to be ultra careful you could wire it through multiple switches that each have to be in a certain position like a combination lock

I tried disconnecting the low pressure electric fuel pump under the floor beneath the seats by pulling off the connecting plug, but it had no effect - the engine still started and ran indefinitely. I think its only needed for priming the diesel, or when its very cold and thick. The rest of the time the mechanical high pressure fuel pump on the engine will suck the fuel through on its own. Which is a pity because that would have been my preference. I imagine the thief conking out a few metres down the road and needing to bleed the diesel would attract more attention than not being able to start the van where it was.

But at least this method is easiest when you forget the secret switch and try to start the engine with it off. You only have to turn the secret switch on, switch off the ignition, and try again.