Central locking problems.

I know other people has posted something similar and i've tried all the suggestions but I wonder if any body has a clue to this problem on my Disco 2.
When you start the car and drive the doors lock correctly and the interior lights go off.
When you stop and turn the ignition off again the doors locks work and interior lights are fine. Get out and lock the car with the fob and you just get a single horn beep and the interior lights stay on for a good 15 mins, No door locks work.
Turning the key in the drivers door only locks that door, again with a single horn beep. The only way to lock up is with the dash lock button and then key in the drivers door lock, again with a single horn beep. This is however intermittent and happens for 95% of the time, the rest of the time it works correctly.
The garage has changed 2 door locks and it's been in for a total of 7 days now and they still seem no nearer to an answer.
Any ideas please?

Horn beep on alarming indicates door open. From what I can gather from Rave, the door open signal is sent to the Body Control Unit from switches in the door locks. Do your interior lights work properly? They would be controlled by the same switches.

If this is the problem, maybe a diagnostics system like Hawkeye could tell you what the BCU is reading - I don't have one so I don't know if they can do this. Otherwise, it would mean replacing all door locks until you find the faulty one. Alternatively, maybe an autoelectrician could wire up something to fool the BCU into thinking all the doors are closed.

Good luck tracking this one down.

Cheers Graham, I think that may be my only answer. Change the locks until I find which one is faulty, just an expensive solution.

Hi

Where about in the country are you?

It would be worth updating your profile so people can see where you are and if your local may be able to help you.

Regards

Ben

Just wondering, If the interior lights dont come on when you open any door and the diagnostic says the door(s) are open when their shut would that imply it's the BCM? Any ideas? Like i said this is an intermittent fault and I can find no chaffed wires or obvious loose connections.