I'm certain it is more than just switches and a timer. There are fades and logic and stuff. I have a nasty feeling it is related to the central locking system ???

Well I don't think it is the Central Locking pump as due to a failure I replaced it today and the fault is still there - http://forum.a8parts.co.uk/showthread.php?p=35590

This one really is strange. It is not the wireing or anything physical....It is just like they are not being automatically enabled.....Leaving the car locked for 3+hrs with a light switch turned on (lights not working) then opening the car and starting and they turn on with the ignition.

Locking the car and they disable again. Leaving any light on and locking the car and the light stays on and when you open, they carry on working!

A very bizarre logic fault somewhere methinks!

Lee

Bad/loose connection somwhere, dry solder joint maybe?:Confused:

ainarssems - I can repeat it perfectly every time and once the lights are on, they all work fine. So it isn't anything random like a loose wire.

It could be a broken connection somewhere that enables the lights and then the leave a light on a start the car after 3+hrs is a back-up or something ???

Loose connections, especially dry solder joints can be dependant on temperature changes. So it is possible once you get the lights on current flow heats the circuit up in the point of loose connection because of increased resistance and as the material expands it makes better connection so it works.

I am not saying that this is definitely the fault, just shooting out some ideas. I have done fair deal of DIY electronic repairs and have seen similar problem in many CRT TV's I used to buy from recycling centre, fixing and selling on some 6-7 years ago. Also you may have heard of Nvidia GPU faults in laptops with similar nature.

ok, you got me curious.

For a 2000 D2, it looks like the door contacts are wired in a way I totally wouldnt have expected.

You may have thought that they would have 2 pins, 1 to earth and a signal back to the central locking pump, or some module, so that it could decide what to do with the signal.

No.

It turns out, the door contact pins actually ground the relevant lighting system to earth, when the door is opened. So, the lights have the relevant +12 feeds getting to them, but only when the door is opened (and the contact switch is working correctly) does it earth the loop and the light come on. If you're handy with a test meter, you may be able to prove this yourself.

So, hypothesising that you have a dodgy contact, on the drivers door at least, then when you manually turn an interior light on, you must be unintentionally grounding the broken circuit, so some things start to work ?

*if* this hypothesis is true, then the following things should also not be working:

Automatic drivers seat memory
Illumination of the boot release switch
Foot well lights
Door puddle lights

Things will be a bit random though as the central locking module also doesnt receive a signal to say the door has opened, or shut, so I would imagine the fancy fading up and down would be eratic - Possibly only working if you opened one of the other 3 doors?

Does any of this ring true ?

ainarssems - The thing is the lights work when cold.....So long as you leave a light switch on when they are not working.....Leave the car for a long period (3+hrs though I don't know the exact timing. Overnight is guarenteed but going to a club is a maybe - I like the lights for passengers). Then when you get in and *START* the car, the lights kick in straight away. Almost certain it isn't a loose/dry situation. However it could be a fault, that the starting overrides.

IT - All the lights are off, so that includes footwells and puddles. I *THINK* the seat memory works, but will check (I bodged the setting a few weeks back so have turned it off, need to read the manual on how to set again).

Boot release switch illumination....Is that inside the car on the drivers pillar. I never use it so haven't looked, but I don't think so. I'm not sure that button is connected that well anyway as I had some issues with it a while back....Hmm. Wonder if it could be the fault ???


The lights aren't on period. Unless I go through the sequence mentioned to ainarssems above. They then will fade down when I lock the car, but then stop. Unless I leave one on (map light say) to keep the circuit live.

Lee

Hi There,

Ok. Just set-up a seat/key memory again and it works fine....Mod the chair, get out. Lock the car. Unlock the car (no lights). Pull the door handle and the chair moves. Lights are still off.

There is illumination on the boot release on the door and the alarm internal sensor buttons.

The boot light works. The passenger glove compartment light works. The red led at night from the rear view mirror works and the internal arm rest led works.

The overhead light, the map lights, the footwell lights, the back main light, the door puddle lights, the vanity mirror lights - Nothing!

Any way to test the grounding thingy ???