Disco 2 Electrical issues

Hi all,

I've got some really tedius electrical issues with my D2.

Currently the alarm/interlocking doors don't work nor do the indicators/hazard lights. If I put the wipers on constant the indicators and interlocking doors start working? Bizzare.

So far I've changed the interior and engine bay fuse boxes with like for like replacements that didn't help. I've put in a new battery that also didn't help. I've cleaned the interior earthing points on the wings and the engine bay earthing points just behind the battery.

I disabled superlock on the BCU as I read this could cause weird issues if the car gets stuck in super lock but sadly that hasn't helped. Unfortnately I'm completely out of ideas!

Quite likely the radio receiver in the roof.

I did think that myself. But when you hit the unlock button the interior lights do come on... Just the doors don't unlock and the alarm does still go off if you unlock with the key.

Failure to unlock remotely is not an unknown issue, and one cause is an an iffy receiver above the headlng, there's already just a few threads on that subject, that's how I know about it.
Unlocking the doors with the key will set off the alarm due to the system sensoring voltage drop, as it designed to do.
Finally when one of the vehicles electrical circuit is misbehaving, then functions correctly when another electrical circuit is used is usually down to a faulty earth connection.

CM0n said:

I did think that myself. But when you hit the unlock button the interior lights do come on... Just the doors don't unlock and the alarm does still go off if you unlock with the key.

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Pressing the unlock button on the fob once should unlock only the driver's door, if things have been set up to their default conditions. A second press of the unlock button should unlock the other doors.
When you press the unlock button can you hear any activity in any of the doors?
How many fobs do you have for the vehicle, you should have two. If so does the unlocking work with the other fob?
Next question, do you have the Emergency Key Access (EKA) code for the vehicle? In the default set-up, you aren't going to be able to get into the vehicled just by unlocking it from the door unless you use the EKA to disable the security system.
As has already been suggested, the second place to check is the RF receiver in the vehicle, the first check is the condition of the battery in the fob, always use a good quality battery, not a pound shop special.
It's not unknown for the latch assemblies in the doors to go faulty, though usually they go one at a time, all five going faulty is unusual but not unheard of, especially if the failures haven't been noticed.
Our mate @neilly has done some good information on the D2 security system which you can find at:- https://www.landyzone.co.uk/land-rover/handy-buying-alarm-info.311291/

If you have access to diagnostics and can change it, then I recommend changing the disarm alarm to "Allways", this will allow the key to disarm the alarm when it is used as well as the fob.

Cheers

Thanks for the replies guys.

Weirdly enought the keyfob does disengage the alarm. You hit the unlock button and open the door and there is no alarm.

But when you hit the unlock button the door locks dont work. Ive since noticed the rear windows and rear wiper also dont work!

Do the locks, indicators and rear windows all run off the same earthing points? Its weird how they all function correctly one the front wipers are on full!

RECEIVER IN ROOF!!!

But wouldn't that stop the door from opening and the alarm being disabled?

Not necessarily. Information fed to the BCU and all sorts of problems can arise.

Nig43 said:

RECEIVER IN ROOF!!!

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iansoady said:

But wouldn't that stop the door from opening and the alarm being disabled?

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Off course that it would

Nig43 said:

Not necessarily. Information fed to the BCU and all sorts of problems can arise.

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^^^ That's wrong... bad receiver means no action from the fob whatsoever

Perhaps I should have explained myself better. Yes the fob wont work with a bad receiver but having gained entry via the EKA code the engine will start but other ancillary electrics eg, wipers, indicators may perhaps not work properly.

Nig43 said:

Perhaps I should have explained myself better. Yes the fob wont work with a bad receiver but having gained entry via the EKA code the engine will start but other ancillary electrics eg, wipers, indicators may perhaps not work properly.

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if you mean that a bad receiver would affect ancillary electrics others than central locking and alarm i must disagree

sierrafery said:

if you mean that a bad receiver would affect ancillary electrics others than central locking and alarm i must disagree

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+1 ^^^^^

I must agree. You need to be looking elsewhere for the problem(s), possibly BCU and/or IDM. You could be very unlucky and have a whole load of separate faults, but that's unlikely.
Check around the fuse board and IDM below the steering wheel for an indications of water damage and also check for similar damage around the BCU behind the passenger's glove box.

The receiver is partially working. When I hit the unlock button on the fob the interior lights come on and the alarm is disabled.
But the actual process of the doors unlocking and the indicators blinking doesn't happen. So far I've replaced the IDM/Fusebox under the steering wheel and the engine bay fuse box. I've checked for water ingress in behind the steering wheel and around the BCU but everything appears to be dry/clear.

I've also noticed that neither the rear windows or rear wiper work n.

Occasionally the car will randomly start working or on occasion the indicators will blink but they appear weak any the locks won't open or close. This weekned I'm going to remove the headlining and check the receiver.. I don't have sunroofs but I'll make sure there's no leaks in that area.

The RF receiver doesn't usually "partially work". It either works or it doesn't, the only "partial" fault is the range problem which can occur. The receiver just takes the signal from the fob, demodulates it turning it into a digital type signal and sends the result to the BCU. The receiver doesn't change or modify the signal from the fob.

As I said in my earlier post, the door latches are known to fail, usually one at a time, but there's no reason why more than one latch could have failed, I had two latches fail in the same month for no other reason than they just failed, that's why I asked whether any activity could be heard from any of the doors while you pressed the unlock button on the fob. Also, can any of the doors be opened from inside by using the manual handle on the doors?
If you can open the doors from the inside, can they then be locked again using the lock button on the fob?

Well I guess by partial I mean the receviver must be receving a signal as the alarm is deactivated and the interior lights come on but the doors don't unlock. When you hit the unlock button on the fob or the internal switch nothing can be heard its not even attempting to unlock.

The doors can be manually opened but not relocked by the fob or internal switch. If I turn the wipers on for instance I can then lock/unlock the doors with the internal switch.

So just confirm the doors do lock with fob or switch but they just dont unlock only if you turn on the wiper?

This is sounding more and more like a BCU problem but it could even be a problem with an earth or wiring around the BCU

To confirm. The doors do not unlock or lock with the fob or internal switch unless the wipers are on full. This is the same for all of other auxiliary electrics if the wipers are on full the indicators, rear windows and rear wiper start to work.

This made me think about poor earths but I've checked the earth mounts on both internal front wings and they look to be ok? No rust or sign of water ingress.