More info needed on immobiliser/passive coil stuff

Earlier today I stripped out my dash again and removed the 10AS unit to check it over. I cannot see any very obvious problems with it, but in the process I discovered an unidentified connector which appears to be coming out of the main harness through the bulkhead.

I also found an orange/??? (can't remember the colour of the stripe) wire which goes nowhere coming out of the grey plug of the alarm ECU. It's attached to pin26 and I think it's for the aerial for the radio receiver for the fob. I accept that this not being connected isn't important 'coz I don't have the unlock functions of the fob anyway, but I was wondering where the rest of the receiver circuitry (aerial etc.) is supposed to be. Does anyone know it's location in a Defender 110?

After hunting Rave, I found the unknown connector appears to be for the passive coil. As I understand it, the passive coil should be part of the ignition switch, or at least mounted on it, I assume near the keyhole end. I don't seem to have one. I have the connector but it's just lying about behind the dash. I also have to mention, that I have never had a fob for the landy, though I have bought one off of Ebay, but as yet I haven't done anything with it to try programming it for mine beastie. Obviously, it aint gonna do much to assist with the immobiliser if there aint a coil to energise it etc.
I do not think I have central locking, I don't think there is an alarm system either, there is, however, a thin 3-core wire hanging out from the headlining just behind the interior light which isn't connected to anything (I assume it would be for the movement sensor thingie if there was an alarm.

So can anyone enlighten me as to how important the passive coil is?
Could that be the cause of my cutting out problems?
Do you happen to have a photo of one in situ I could have a look at?

Hawkeye displays 20 items when looking at the program page of the ECU and item 13 is set to YES for Passive Immobilisation. The option to change this to no is there, but every time I tried to change this setting and save or write this it always re-set back to YES so it appears I cannot switch it off.

Once again I thank anyone in advance if you can shed some light on this one for me.

Time for bed, I'll check back tomorrow morning after work.

Cheers,
Ron.

The passive coil fits around the ignition barrel and senses the proximity of the key fob. As far as I can tell it only operates the immob function and has nothing to do with the alarm or key fob button operation.

I believe the unconnected wire from pin 26 is the actual alarm aerial. I read somewhere that extending this can improve the operating range.

The three core wire hanging from the headlining would be for the movement sensor that on my Defender is mounted at head level just behind the door pillar where the seatbelt upper mount is.

Thanks once again for your response Shifty, I was more curious about the fact that my immob seems to be switched on to receive a signal from the passive coil which isn't there. At this stage, I am having to assume that someone in the beastie's past has tried to bypass or dis-connect the immobiliser. However, for the moment, I will go on the assumption that the engine wouldn't start and run at all, or at least, as well as she does when she isn't in a state of PMS and cutting out if it was the immobiliser which was killing her. The only real reason I have for suspecting the immob ECU as part of the cause is the fact that my interior light, which is largely controlled by the 10AS, does not work off the door switches when she has died, but works normally when things are running properly. I now intend to re-build my dash with the 10AS box in a more accessible location and take multi-meter readings from all the pins on both plugs so I can compare them when she is running normally and not running at all. Then hopefully I can do the same for the engine ECM under the seat. Then I will be tracing back all the wiring associated with the interior light on the off-chance that I may find a dodgy header behind the fascia panel or something of that ilk. I do remember once (the first time she'd died in fact) that while I had been sitting waiting for my rescuer, I had been playing with the radio/CD player (which at that time was sitting loose on the dash) and I heard the typical sound of a short to ground and the radio, hazards and a few other things went dead on me. Yes there were Scotchlocks in there, I replaced the fuse and everything came back on, but died again a few minutes later, but the fuse was ok. So there is something suspect in there. This has never happened again since, but I have replaced the radio unit with one of my own and wired it in tidily to the existing wires, without Scotchlocks I might add, but I'd never taken the fascia out to see what had caused the short in the first place, I had assumed it was simply the rough wiring of the botched in radio.

Rave has a nice list of the Headers and Splitters and diagrams of their connections, but I cannot find any reference to the two blue headers which are in the same compartment as the engine ECM. One has a number of wires which come and go on the same section of the harness as the red ECM plug and the other is connected similarly to wires in the harness for the grey plug. I haven't been able to find them in Rave and they are not visible in any of the photographs of the under seat box shown for the ECM or Engine compartment fusebox & relays etc.

Can you shed any light on these?

It's beginning to get a little frustrating now, but I will keep at it, even if I end up getting someone like TD5ALIVE to sell me a complete 10AS, with fobs & passive coil, and an engine ECM, which I am assuming they will be able to set up to talk to each other before they post them out to me. Probably the expensive option, but that idea will be a last-ditch effort only if I cannot solve it in the end by other means. At least then I would be 100% able to rule out any ECM/10AS/Immobiliser as being the cause of my woes!

Cheers Shifty.
Ron.

Oh God you must be getting fed up with me, I just re-read my post and realised that what was meant to be a quick reply has, yet again, turned into one of my epic tales......... Sorry, I just yak :blabla: a lot :blabla:, it comes from living on my own, being a trucker and not having a social life!!!! :blabla::blabla::blabla::blabla::blabla: