Alarm/immobiliser

kevind · Mar 28, 2021

Hi. Recently bought a96 300tdi manual disco 5 door. Previous owner/s have bodged wiring big style. I have now managed to get car recognising fob, opening doors, all windows, lights on dash and headlamps, wipers etc working. But, only way car will start is with bodge previous owner created. On fuse box on drivers side there is a plug (3wires) he has cut the white red stripe and scotch blocked this into a large black in harness to the left of steering column that I think is full of alarm wires, they are all black. Without this the immobiliser won't come off, or show light on dash, with the bodge light on dash works and car starts. I have checked all fuses in passenger and engine bay, spider has wired bypass, replaced fuse box, multi function box, and central locking alarm box. Any ideas chaps.

discool · Mar 28, 2021

Okay starting from the beginning, the three wires are from and aassociated with the ignition switch 1 2 and 3 positions, with out checking, the white/red is to the starter feed when cranking.

There is a thick multi wire harness that includes a few circuits other than security and any black wires found are earths terminated below in the footwell.

“The immobiliser won’t come off” so what does that mean? the vehicle is immobilised and wont start and unable to remobilise or its permanent mobilised and starts and runs ok.

Its possible that the spider immobiliser circuit to immobilise the starter function was faulty, and has now been bypassed hence the modification to the white/red wire that was done.
If the spider has been fitted with the LR bypass then it’s possible that there wont be any dash
lamp indication.

kevind · Mar 29, 2021

discool said:
Okay starting from the beginning, the three wires are from and aassociated with the ignition switch 1 2 and 3 positions, with out checking, the white/red is to the starter feed when cranking.

There is a thick multi wire harness that includes a few circuits other than security and any black wires found are earths terminated below in the footwell.

“The immobiliser won’t come off” so what does that mean? the vehicle is immobilised and wont start and unable to remobilise or its permanent mobilised and starts and runs ok.

Its possible that the spider immobiliser circuit to immobilise the starter function was faulty, and has now been bypassed hence the modification to the white/red wire that was done.
If the spider has been fitted with the LR bypass then it’s possible that there wont be any dash
lamp indication.

kevind · Mar 29, 2021

Hi Discool, the immobiliser light will work with bodge wire in place, ie with car technically locked then releasing drivers door switch alarm works, flashes indicators immobiliser active. Press fob to open car immobiliser light goes out car starts. Without bodge wire car locks unlocks but won't start and no immobiliser light on dash. I have tried this with spider in place and not in place, doesn't make any difference. Hopefully this clears it for you. Your help welcome. Kev

discool · Mar 29, 2021

kevind said:
Hi Discool, the immobiliser light will work with bodge wire in place, ie with car technically locked then releasing drivers door switch alarm works, flashes indicators immobiliser active. Press fob to open car immobiliser light goes out car starts. Without bodge wire car locks unlocks but won't start and no immobiliser light on dash. I have tried this with spider in place and not in place, doesn't make any difference. Hopefully this clears it for you. Your help welcome. Kev

Hi, Okay a 12v supply from ignition switch when in position 3 on the white/red wire via fuse 17 goes to the starter relay coil, somewhere along the line the spider interrupts the 12v supply to the relay therefore the engine doesn’t crank.
So the modification would suggest that its to provide the missing 12v to the starter relay to enable cranking and starting the engine, a volt meter will confirm.
Its a possibility that the spider is faulty hence the modification, u may find some interference with the wiring at the starter relay, otherwise leave the mod alone, if you are happy to do that.

kevind · Mar 30, 2021

discool said:
Hi, Okay a 12v supply from ignition switch when in position 3 on the white/red wire via fuse 17 goes to the starter relay coil, somewhere along the line the spider interrupts the 12v supply to the relay therefore the engine doesn’t crank.
So the modification would suggest that its to provide the missing 12v to the starter relay to enable cranking and starting the engine, a volt meter will confirm.
Its a possibility that the spider is faulty hence the modification, u may find some interference with the wiring at the starter relay, otherwise leave the mod alone, if you are happy to do that.

kevind · Mar 30, 2021

Thanks for that, so where is the starter relay located and how do I identify it, would like it standard for the future. Cheers

discool · Mar 30, 2021

kevind said:
Thanks for that, so where is the starter relay located and how do I identify it, would like it standard for the future. Cheers

Behind the footwell kick panel drivers side, on the lower level there’s three relays the one u want is in the centre, its yellow, or was when the vehicle left the factory.

My immobiliser failed around seven years a go, by removing the 12v supply the ignition system, but it wasn’t a great issue in installing a single wire as an overlay to the existing circuit to provide the switched 12 volts.

Alarm/immobiliser

kevind

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discool

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kevind

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kevind

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discool

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kevind

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kevind

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discool

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