Central locking and alarm dead, so is car!

Hi all, help needed yet again please for my 1994 RRC 3.9 V8.
Central locking was working but the alarm only triggered from the passenger door, trial and error lead me to the pin switch on the drivers door not working. Found a working pin switch from some mk1 discovery bits I had (as you do!), managed to fit this and now had central locking and alarm activation on drivers door, that was yesterday. This is today, came to unlock it and the central locking didn't work, battery is brand new and shows no signs of dimming the lights when trying to start the car so I'm assuming the dead central locking means the alarm has cut power to the starter motor (which it's supposed to do) . There lies the problem, how do I get the central locking and alarm circuits back up and running? Ideas and solutions most welcome please, thanks, peanuts

OK, I've now established the alarm ECU controls the central locking and I've got 2 alarm ECU's from the mk1 discovery box of bits, when it stops raining (probably tomorrow now) I'll see if they are the same unit (same year cars) and have a play, anything I should be wary of please before I knacker something completely?

peanuts01 said:

OK, I've now established the alarm ECU controls the central locking and I've got 2 alarm ECU's from the mk1 discovery box of bits, when it stops raining (probably tomorrow now) I'll see if they are the same unit (same year cars) and have a play, anything I should be wary of please before I knacker something completely?

Click to expand...

Depending on the D1 security ECU’s (there are two types) the fobs for the later ECU are programmed to match, so hopefully u have a fob for each of the ECUs u have the “box of bits.

discool said:

Depending on the D1 security ECU’s (there are two types) the fobs for the later ECU are programmed to match, so hopefully u have a fob for each of the ECUs u have the “box of bits.

Click to expand...

A key turned the drivers door lock also operates the master central locking actuator.

Thanks for that but unfortunately, never had any fobs.

peanuts01 said:

Thanks for that but unfortunately, never had any fobs.

Click to expand...

Okay, if both of the ECUs are green coloured then no point using them, unless using RemoteKey to supply and programme a replacement fob to match the ECU, if they still do that now... that is.

So if u just want the CL operating than there kits available consisting of an ecu plus remote fobs and a master actuator, the existing slaves in the other doors can be reused along with the wiring, a wiring diagram comes with the kit and the kit cost is “peanuts”.
Or go the whole hog and have an alarm-immobiliser-central locking kit... but that wont be “peanuts”.

Or find out why the existing system isn’t functioning

Thanks once again, the ecu's are black, the D1 was AMR2109 with a blue spot and the RRC is AMR 2106 with a red spot. Bought one off eBay for £40 and fingers crossed that was the problem and it all works. If not, then your suggestion of a separate system would seem to be the only way forward, (otherwise I'll have to get a sparky out as it's stuck on the drive and my electrical 'prowess' is very limited) do you know if one, or both, of the aforementioned kits will get round the problem of the car not starting please? Cheers.

Ok the early security ecu then, but with up to date frequency 433MHz the one with the co-ax plug antenna.
Replacement is just that nothing other than unplug the existing and plugging in the replacement, works easy via the drivers door lock micro switches at the rear of the lock operated by a cam... which has been known to break.
The fob was early on an option for remote CL so the system works as it should manually via the door lock. The single button fob can be DIY programmed, there is a procedure to follow stated in the workshop manual... switch on and off the ignition, open the bonnet, hold the bonnet switch down, stand on one leg... u get the idea.
You may have a large relay close to the ECU, supplying alternative voltage to the master actuator, open- close when the fob or door lock is used,
Door with the actuator trying to move but not operating the locks could require a very slight adjustment of the actuator mounting plate, slacked the 4screws.
So that about it for the central locking.

After thats sorted.... then... move on to the alarm if it has issues. Not starting run a temp 12v the the coil + terminal and try.

Yep, the AMR2109 is 433MHz but the AMR2106 (mine) is 418MHZ. Just replaced the micro (pin) switch and the cam is ok. Tried a fob I got of eBay on the D1 and, as usual, failed miserably. (on reflection, as I write, I wonder if it's a 418MHz fob and that's why it didn't work on 433?) There are several large relays close to the ecu and the mounting tray is rusty at the back, not a good sign! The central locking was working on both front doors but, the alarm only worked on the passenger door, hence replacing the pin switch and getting the drivers door to work the alarm too, well for a few hours until something broke, which is where I'm at now, I'm just hoping it burnt out having not been used for years (the car hadn't moved for 2 years when I bought it). Not the greatest of mechanics/technicians so please point me in the right direction regarding attaching the 12v+ to/from the coil to/from? Sorry about my ignorance on these things. Thanks again, peanuts.

Okay, AMR2109 requires a fob with the same 433MHz frequency, so with the disco there was two fobs depending on the band of VIN of the vehicle compatible with AMR2109, but as aways there are two numbers AMR3423 and the most up to day being AMR4867 I’d go with that if available, LR then went to the more advance system with a two button fob.
Until u get a compatible fob, setting and unsettling the alarm can still be done with the key in the drivers door lock, normally that would be the same time as locking unlocking,
Cannot tell u which relay, my RR parts catalogue doesn’t cover your year of RR.
Assume the engine cranks on the starter, and not starting so are u getting a spark and fuel at the plugs, if not check your getting 12v at the coil, if not then a temp lead from the battery +, to coil + and then crank the engine the coil is where the EFI picks up its info start the pump to provide fuel.

Brilliant Discool, thank you. When 2nd hand ecu arrives I'll swop, if no go, I'll have a play (as is my want lol). As for the fob, me thinks best left to keys!. Cheers, peanuts

Not sure if this would help but you aren’t far away so worth thinking about.
My Rangerover LSE came with 2 alarms fitted. The standard Landrover one and the Clifford one which shouts at you if you stand too close to the car (I am not joking).
The Clifford Alarm fobs operated the central locking as well as the alarm.
Having 2 alarms just got annoying. Especially when one of them reset itself 20 seconds after you’d unlocked the car.
I set about removing the Clifford Alarm as carefully as I could.
It was a heart stopping moment when I had the whole car totally disabled but after a lot of wire chasing it came good.
I now have a box of bits which make up a Clifford Alarm and remote fobs.
Whether you could or would want to wire these into your vehicle I don’t know (Clifford are very restrictive over who they give the installation instructions to). But let me know if you are interested. £20 donation to our local church would cover it.

Thanks for that kind offer however, if I'm beaten by the Range Rover alarm I think I'd be suicidal with something more complex . I have to admit to admiring your spirit in going for it in the first place , way beyond me, I'd still have two alarms, (the fact I haven't even got one at the moment is neither here nor there lol.)
Just to keep you up to speed Discool. swapped the alarm ecu, no difference, swapped the alarm relay (AMR 1088), no difference, and I do have power at the coil. Wish i could read a wiring diagram! But, that said, how can a wire fail overnight? I'm bald anyway and that little patch I keep scratching is not getting any better.

So is the central locking now working on the fob?
Do we know that the starter motor still works?

Never had a fob, central locking and alarm only worked on the key on the passenger side then, after pin switch replacement, drivers side for a few hours.
There's no power getting to the starter motor (it's what the alarm module is programmed to do), hence no light dimming when key turned in ignition, which usually happens if starter motor is dead.
Going to try all the alarm electric circuit tests (hopefully) as per 1995 Trouble Shooting Manual, providing weather stays fine

Is it not an immobiliser/key synchronising issue?
Is it possible that the alarm/immobiliser was previously disabled but in fixing the driver’s lock it became re-enabled? https://www.landyzone.co.uk/land-rover/resetting-alarm-immobiliser-sequence.200118/
If this link doesn’t work then there’s a posts from Splasher in 2010 on that topic.

Many thanks for that, my old P38 had an EKA code (and I did have to use it once) but didn't think my RRC would have with not having a transponder in the key but, noting ventured, nothing gained so, I tried the start of the sequence as detailed but zero from the alarm so couldn't go any further. Please keep your thinking cap on

Just been talking to my garage. Owner is a Landrover fan who especially loves late classic rangerovers. His suggestions were alarm spider under dashboard (presumably what you have replaced) or bad connection in harness. He has had a similar age disco where the loom passing through (passenger side?) door pillar had a connection green with mould and that produced similar symptoms. Bit worried about new alarm ecu, thought that had to be coded to engine ecu?

Thanks again for the interest, yes, the spider is the ecu with all associated bits coming from it, I replaced this on my same year D1 and never had a problem with engine ecu not recognising it (it has to be the same AMR code and MHz), fingers crossed it applies to the RRC too. Will be checking as much wiring as I can get to (71 year old fingers don't seem to get where 21 year old ones did), didn't happen yesterday so hoping today pans out better, it's on the drive so not in the way, just frustrating.

I've been watching this for a while, and haven't really much to add to the advice already given, other than to try and make sure you have a working fob .... to this end, I'd advise getting in touch with:-

https://www.technozen-electronics.co.uk/

to see if they can assist - he seems to specialise in older stuff, including LR...

In terms of reading wiring diagrams - the LR ones are in an unusual format - I'd suggest some perseverance, as they do click eventually .....( or they did with me )

(I've just fought something of a battle with my D1 MFU - the little sh*t, so I feel for you ..... though I won , and I now have a D1 with no MFU to cause more problems )

( no affiliation etc. ).