I presume its called a convenience unit (controls the electric windows, central locking etc)?
So I'll explain my problem, or problems more like.

First off its an N reg 300tdi disco.

The problems started with the rear electric windows being very temperamental, one day they'd work the next they wouldn't, and so on.

The next problem was that when I tried to unlock or lock the car through using the remote central locking fob only the passenger doors would unlock/lock and not the drivers door, but when using the key I could lock the drivers door and in turn it would lock the rest of the doors. This wouldn't work for unlocking though, I had to press the fob and unlock the drivers door using the key.

The next problems all happened today, first off when I drove to work this morning i noticed that just before the drivers window got to the top when closing the central locking (apart from drivers door) would lock and unlock, this problem continued throughout the day.

When I got home I thought it was about time I should take a poke around, so I first took the window switches out from in-front of the arm rest in the front. No loose connections from what I could see.
I was playing around with the switches and noticed that the 'click' noise that usually came from the passenger side footwell when the front windows were winding up or down wasn't happening when I pressed the rear window switches (which had stopped working a couple of weeks ago all together).
So I followed the sound and got to this box (unless my hearing is particularly bad lol)



I then made the mistake of moving it, which set it clicking away and the hazard lights off - but the odd thing was, it wasn't the hazard lights as when I pressed the hazard light switch and you could hear that flasher relay was clicking along in time with the box pictured above.
I tried unplugging one of the connectors but it set the alarm off.

As i was about to disconnect the battery the hazard lights went off. So I refitted it. The problem of the unlocking and locking also stopped.
But now i cant lock all the doors using the key in the drivers door. The fob still unlocks/locks the passenger doors though.

I hope you've managed to stay awake through that, i am known for my thrilling story telling.

And my questions after all that is, is it that unit that is f**king everything up or not?
And if it is, can I swap it straight over from one from another disco??

Before anyone asks no i haven't been doing any really deep wading to get it wet.


Thanks very very much if you can help me !

alarm ecu is next to window ecu ,inside door theres a micro switch for cl wire runs around window channel or should do it may be getting pulled by window moving

I had a prob with mine when I wound window down it would lock turned out to be a wire in the multiblok connector on actuator a wire had been pushed out making a iffy connection pushed it bk in and all has been fine !

Okay I'll check it out . Could I straight swap my window ecu for another? Im thinking that's what's causing the rear windows to not work.

Rice said:

Okay I'll check it out . Could I straight swap my window ecu for another? Im thinking that's what's causing the rear windows to not work.

Click to expand...

Re the window ecu and rear windows fault. This is a very common problem, open the ecu and you'll find a couple of 'dry joints' that need re-soldering. Do that and there's every chance they'll work again.

My rear windows wont work when I start up. 10 mins later they are working fine - this delay is always there - happens everytime. Dry joints or some other problem? Front windows fine btw.

Time to remove the door card and look at the operating rod from the drivers door actuator (master) to the door lock, this acutuator controls the locking-unlocking of the other four doors (slaves) so if they are ok so is the electrical supply also at the rear of the lock barrel at the micro switch.

Hazzards! thats normal if the alarm ecu touched, the alarm ecu the hazards flash, if your door were locked at the time they would unlock, the ecu has an inertia crash sensor built in to do this resetting is by turning the ignition switch on/off that info is in the owners hand book.

Aways a good idear to remove the supply if you are unsure when working on electrical stuff live.

Thanks for the replies chaps !

Fixed the drivers door not locking/unlocking last night, it was two broken wires, so all works as it should now!
Just need to sort the rear windows now!

Hi just a thought but is the rear isolalator switch
on Cheers Stuart

Haha, no, although that would be funny if it was.

Took out the window ecu earlier, had a look over it and realised one of the solder connections on the back was broken and caused a dry joint (if that's how you describe it!), so re soldered it back on and now they work perfik! First time I've fixed a circuit board break, I was beaming with satisfaction when I plugged it back in and they worked !

Many thanks to those who replied!

Rice said:

Haha, no, although that would be funny if it was.

Took out the window ecu earlier, had a look over it and realised one of the solder connections on the back was broken and caused a dry joint (if that's how you describe it!), so re soldered it back on and now they work perfik! First time I've fixed a circuit board break, I was beaming with satisfaction when I plugged it back in and they worked !

Many thanks to those who replied!

Click to expand...

That's just awesome, so pleaszeed for you.

Scus the typing but I'm in training for tomorrow nights 60th birfthday celebrations - ie I'm getting shîtfaced !!