Central locking problem

Brian S · Feb 10, 2010

Hi, I have a 1994 M reg Discovery with a central locking issue.

The central locking used to work except the front passenger door, which I lived with. The fob worked fine or the drivers door would open the rest of the doors.

Now there is no central locking. The Fob does not work and the light below the radio that used to flash is now dead.

I can only open the doors the old fashioned way.

I thought there was a central locking ecu under the glove box but it was not there, the Haynes manual said behind the drivers kick panel, but it is also not there.

Can any one offer me some other things to try or places to look.

Cheers.

nicedayforit · Feb 10, 2010

The alarm/locking ECU is behind the glove box on the passenger side.
It's a green box about the size of a packet of ciggy's mounted on it's side on a rack beside a number of relays.
You can't miss it it has a coaxial aerial plug in the side of it just like on a tv.
It must be there otherwise the locking wouldn't have worked previously.
It's marked AMR... something , can't remember number.

discool · Feb 10, 2010

Two things here, first is the red CATS lamp is a radio thing if it's the lamp positioned to the lower right of the on/off vol switch try pressing the BND button for aprox 3 seconds to activate, and then there's CL.
The CL and alarm are in one unit it's not unknown for this ecu which is/should be behind the glove box to go faulty.

discool · Feb 10, 2010

You may find your ecu for the alarm/CL ecu is black, for the 300's alarm ecu is green and the CL ecu is black

Brian S · Feb 11, 2010

Cheers guys, I'll have another look in a bit. Its a 300 shape.

I am sure the little LED below the head unit used to flash when the car was locked.

discool · Feb 11, 2010

Brian S said:
Cheers guys, I'll have another look in a bit. Its a 300 shape.

I am sure the little LED below the head unit used to flash when the car was locked.

The 300 series started with the 1995 model year so u have one of the originals. I should have said the later 300's with a two button fob there the ones with seperate modules.

If you are talking about CATS Computer Anti Theft System light on the radio it only come on when the ignition is switched off.

If it's a LED fitted into the top of the dash perhaps this has been added at a later date and you have a non standard alarm/central locking system fitted.

alexdon · Feb 11, 2010

Brian S said:
I am sure the little LED below the head unit used to flash when the car was locked.

I assume the light you mean is in the middle of a narrow horizontal plastic piece directly below the headunit, this is the alarm/locking indicator. I too have one of the early 300s which has the single button fob and the same light.

Brian S · Feb 11, 2010

alexdon said:
I assume the light you mean is in the middle of a narrow horizontal plastic piece directly below the headunit, this is the alarm/locking indicator. I too have one of the early 300s which has the single button fob and the same light.

Thats the one. Since the CL stopped the light has stopped

discool · Feb 11, 2010

Now that's sorted it's back to plan A ... find the ecu

alexdon · Feb 11, 2010

It sounds as though it is the ECU. You need to drop the glove box to be able to see it. This may help you ECU

Brian S · Feb 11, 2010

Cheers guys. A friend of mine is picking up a Disco tomorrow for the running gear. I hope he will have one for me to try.

mburton2 · Aug 10, 2010

THREAD RESURRECTION!
My 94 300tdi Disco, has NO remote....Just keys.
Unlocking the Drivers door, used to unlock the other doors....But it cdoesnt anymore!....any thoughts on where I should start looking for a cure?
I've checked fuses...cant find a suitably labled relay.....

discool · Aug 10, 2010

Single button fob system, the drivers door actuator controls the central locking alone and unlocks the other four doors.
With a two button fob drivers door actuator controls the alarm - central locking ecu which unlocks the other four doors.
You must have the single button as you can start your car with out the fob with a two button system it has passive imobilision u see, unless it's all been removed.

So check the fuse and then you will have to check the actuator for power and function they are known to go faulty also there's a wiring diagram in the Haynes manual and a bit more info is in the forum so do a search.

Central locking problem

Brian S

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nicedayforit

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discool

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discool

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Brian S

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discool

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alexdon

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Brian S

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discool

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Brian S

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mburton2

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