problem with alarm/immobilser?

Hi every body,
hope some body can help with this problem iam having,driving along and hazard lights came on pulled over to sort it out and found it to be black box under glove box,so disconnected it got back in disco wouldnt start,reconnected it hazards flashing engine starts,left engine running disconnected it all ok,stopped car come to restart would not start or lock on central locking had to lock all doors individually,got a secondhand one from local breaker which sorted hazards flasing and starting issue but not central locking,left it a few weeks put old one back on reprogramed fob everything fine but this has occured a couple of times now,keep swapping and changing is getting annoying especially when your driving along and hazards suddenly come on and you cant indicate to pull over.any help would be much appreciated cheers
p.s the black box has a code on it which is amr2109 freq 433mhz and the disco is 300 tdi 1995 m reg

Have a look round where your "black box" is, if you have a green box there also it could be that at fault. It has an inertia switch inside which activates the hazards in the event of a crash. If it is not secured properly it can cause the symptoms you have.

However, I am not 100% certain that the discos with the amr2109 (one button fob) had this, it may have only come in with the later amr4886 system (2 button fob).

unplug the bonnet switch ...maybe u are lucky

cheers guys,will have a look tommorrow in daylight,what is this box called or known as?

compo72 said:

cheers guys,will have a look tommorrow in daylight,what is this box called or known as?

Click to expand...

It's known as an ECU or "Electronic Control Unit".
If as alex mentioned above the inertia switch has activated, just buy turning off and on the ignition will reset it also let you use the central locking which would have been overridden as the system unlocks the doors if they were locked at the time of activating of the switch.

had look for green box but couldnt find one so did what discool said and hey presto it worked then just reprogramed alarm fob and everything good for now,just the alarm siren to sort out which ive ordered one of ebay which should be here this week,just like to say thank you to all