Central locking and alarm dead, so is car!

Hi Disco1BFG, thanks for watching, unfortunately I don't have a working fob, car didn't come with any fobs that I can have repaired so, it's keys only I'm afraid (worked before .......... ish)
I intend to keep fighting it, not that I have much option as it's a bit big for a garden ornament
Normally I'd rope my son in on something like this but as he's self employed and just got a months continuous work, that won't be happening.
Keep thinking people, please.

I had one of those 'stab in the dark' thoughts, what if the replacement alarm ecu was also duff so, I contacted the seller, jbs4x4, in Lye and James immediately came back and said, "not a problem", and sent me a tested one out the same day at no charge, and said "just return it if that also doesn't work", brilliant service I have to say, the mere fact that that didn't work either is a bit of a bummer (to say the least) but now I know I've got to carry on delving deeper

Well atleast thats rules out the ecu, good service from jbs

So I thought the main issue was with the vehicle not starting, if the engine was immobilised then a 12v supply to the ignition coil and starter would be missing but I believe that u have both, therefore there should also be a supply supply to the EFI ecu which will start the fuel pump and injectors as and when required.

If you had a the later and fully functioning passive immobiliser then you wouldn’t be able to remobilise the engine without the fob being present near to the ignition switch, of course the system does remobilise when initially unlocking the vehicle remotely, but then if you didn’t bother to start the engine then after a short period of time the system would re-immobilise the engine, thats how it works, which would show as indication in the dash display.
And there would be an access code available to totally override that security, a get you home function.

I thought that your security system had the black control unit which would use a single button fob, so NOT the latter passive system, which isn’t really necessary as the door lock will work just fine, on a functioning system that is.

But I've never had a fob, it's only ever locked and unlocked on the key (in either door to unlock but, if locked on the passenger side, the alarm would go off if unlocked on the drivers door) and it all worked for that brief period one day, then failed completely in about 18 hours. This is why I'm so confused (and yes I do use them lol) what can go wrong with stationary locked car overnight? Would it effect the EFI ecu (or any other ecu ................ I know my luck) if, after I'd got the alarm and central locking all working, as I did, I didn't try and start the car that night? Is this muddying the water still further?

It appears that its a possibly that your alarm system is permanently set, so when u lock the passenger door it the alarm detects a voltage drop as the do and therefore activates the alarm, but that shouldn’t happen

The question is why, as the locking the passenger door is like any other door the vehicle, if a key is used its mechanical, the key turns and via an operating rod operates the lock mechanism.
The only item that is responsible for central locking al the four other door is the master actuator in the drivers door when u use a key, for all five door to lock remotely/electrically is with the fob.
I think i’ve already mentioned that the key can set the alarm alongside with the immobiliser, identical if u had used a fob.

The security system was use up to 1994MY with a disco, it a long while but I remember the key setting function needed the key held in a position for a second or two to set the security system, I took that as meaning u could lock the vehicle without setting the security system.
A long while ago so may be wrong, so would need to read the owners handbook for a 200 series disco again... I won’t hold my breath.
Or RR handbook of course, my 3.5 didn’t have a security system until I fitted one.

I've read the owners manual, that didn't help. I've got the 1995 Workshop Manual and it's that and Electronic Troubleshooting Manual that I'm using to try and trace any wiring faults, none found so far. The only other thing that came back to mind when I was talking this through with another mate was that when I went to find power to the coil after it all failed, it was only 11.75 volts, it was a new battery 2 days before, could an earth drain have happened and took power from the battery and left the alarm in an armed state and that needs clearing? Somehow? Considering it's a different alarm ecu now. This really is clutching at straws time.

Hi, 11.75v is perfectly fine to start your engine, when cranking battery voltage can drop to 10v and possibly a bit lower but even on that limit the engine will still fire up, which happens sometimes with my disco when its left for 2or 3 weeks untouched.
The battery battery voltage will drop over time due to the various items onboard that have a memory to maintain, radio, clock, any ECUs and of course a security system.
Also are the plug sparking, its there fuel from the injectors ? And check those micro switches in the drivers door againi believe theres two.

peanuts01 said:

I've read the owners manual, that didn't help. I've got the 1995 Workshop Manual and it's that and Electronic Troubleshooting Manual that I'm using to try and trace any wiring faults, none found so far. The only other thing that came back to mind when I was talking this through with another mate was that when I went to find power to the coil after it all failed, it was only 11.75 volts, it was a new battery 2 days before, could an earth drain have happened and took power from the battery and left the alarm in an armed state and that needs clearing? Somehow? Considering it's a different alarm ecu now. This really is clutching at straws time.

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I find clutching at straws to be a bit self defeating, so, I'd go back to absolute basics:-

discool said:

Also are the plugs sparking, is there fuel from the injectors ?

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^ get these two bits sorted, Discool gave some instructions in post #10, and go from there .....

Also, for example, if the starter turns the engine over when you independently energise the solenoid - does it also turn over when you energise the starter relay - either by jury rigging it, or bypassing it ? - keep working backwards from the "load" until you find the problem - loads of vids of the tube about electrical trouble shooting - some really good ones on the "south main auto repair" channel IMHO....

Found 'south main auto repair', yep there's plenty if videos, just need to find the right one lol. I have also now bought a relay tester and, despite swapping the alarm relay with my old disco (now sold) and the alarm still working on that, this tester says it's duff, it also found a green YWB 10032 was also not working, I've got both on order now so, as you say, back to basics (and they don't come more basic than me!), so I'll make sure that at least these are working and then go from there. Many thanks yet again!

I’d be worried by that voltage drop. What voltage are you getting at the battery?

The battery read the same as the coil, since charging it up it's not dropped (12.66v) but there's nothing live, well apart from the clock. The relays were at DHL in B'ham at 6:46 this morning so maybe delivered today?

Well the relays arrived and I duly fitted them, hoping they would be the panacea, no such luck, nothing changed. So now I'm in back to basics mode as suggested but I've hit a snag, I can't reach the starter motor, not from above or (when jacked up) underneath, am I missing a trick here please?

I was recommended by a friend to try Gav at 'Keepers Cottage Classics' in Bramshall, he admitted it was out of his territory, he's a Series and Defender man but to try Greg at LRX in Leek. I did and explained the scenario to him and he said he felt the non starting and the central locking/alarm problem were two different things (yes I was/am still baffled) and that I should find the starter relay (as has been suggested) and he told me where to look and what to look for (behind the drivers side kick plate there are 2 rows of relays, it was probably the bottom row of 3 and it was a 4 pin relay, so I found that as the other 2 are green 5 pin, it was the yellow which was the 4 pin) then to short out pins 30 & 87 and see if the engine turned over, it did!, then to try it again with the ignition on and, yep, she started. So now I have to trace the leads back from the ignition to the relay to see which/what has failed, this is beyond me as my electrical skills stop at wiring a plug. So, I've rigged an old 1960's flasher switch off one of my old minis (never throw anything away, you just never know) to pins 30 & 87 in the starter relay and can drive the car. Where to start with the central locking/alarm problem is now as far away as it ever was so, ideas still welcome, as they are for an easy way a layman like me can follow to find the starter wiring issue. That bottle of wine will help I've no doubt, cheers

On the alarm issue, did I mention checking for corrosion in a connector in the windscreen pillar (near side I think)?

Corrosion on a RRC surely not .

Funny you should say that, my son and I have been playing with the electrics on the near side footwell and there's a fair amount of corrosion. My son carried out tests as per the Electric Troubleshooting Manual and found there was an earth distribution point problem to both front door locks (can't find where they go to earth, manual doesn't say) and in the process of pushing wires around, set the alarm off! A bit more pushing and pulling and the c/l and alarm worked, only the once, but it worked. It then persisted it down and we stopped but now know that the fault is somewhere in the wiring in that area, tomorrow I will take every plug apart, clean it and reassemble, fingers crossed ..............

peanuts01 said:

Funny you should say that, my son and I have been playing with the electrics on the near side footwell and there's a fair amount of corrosion. My son carried out tests as per the Electric Troubleshooting Manual and found there was an earth distribution point problem to both front door locks (can't find where they go to earth, manual doesn't say) and in the process of pushing wires around, set the alarm off! A bit more pushing and pulling and the c/l and alarm worked, only the once, but it worked. It then persisted it down and we stopped but now know that the fault is somewhere in the wiring in that area, tomorrow I will take every plug apart, clean it and reassemble, fingers crossed ..............

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We have the same problems with the block connectors on the P38 bottom of the A posts. Cut out solder and heat shrink the wires. They're only used during assembly.

Glad you're making progress... have you looked in the D1 ETM for the earth points ? very similar vehicle after all...

peanuts01 said:

I will take every plug apart, clean it and reassemble,

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Best way I have found of getting rid of the "green crusties", is to "boil" the connections in Bakers fluid, AKA zinc chloride ( it's a flux ) - should be available in most engineers merchants ... its not cheap (£15 ish for 250ml ), but is very good.... ( by boil, I mean put some BF in a ladle, warm it up, and put the connections in ... you'll have to de - pin each connector, else risk melting the thermoplastic housings, which is a proper RPITA , but it does cure crustiness )

Minor green crusties can be removed with CAIG deoxit - on the bay - again, not cheap, but good for spot treatment...

Once you've solved the problems, then as post #38, getting rid of the connectors can be a good idea - just make sure you can still take the doors orft for access for welderizing

3 brilliant posts, I really do thank you for taking the time to write. Weather permitting (and whether or not the intercooler arrives today for my sons Volvo) I'll be on it today. I've ordered some CAIG DeoxIT, seems like something that should be in the tool box anyway, cheers. Being a 60's/70's lad I was brought up on Scotch Locks and so was wondering if I found the earth wires (after doing connectors) I attached secondary leads to them both and took them to a new earth as a temporary measure and, if it worked do soldered joints, just a thought.