2002 Golf Mk4 V6 4 Motion - electrical issue ... sorry! Need some assistance

[V6Mk4Golf]

Ok, hope you guys / gals can help, I have a gremlin on my 4 motion (2002 Golf V6 4 Motion, 2.8 24v 205bhp) that is really quite irritating ...

So ... there is a parasitic drain of the battery, about 0.5A, enough to drain what is a relatively new battery in 3 to 4 days. Here are the symptoms and what I have done to (unsuccessfully) try and diagnose it.

Ok so first of all the interior lights don't work. I've read a lot about door locking modules needing to be re-soldered or replaced etc etc but I am not sure this is relevant since none of the lights work when I open either door (3 door) or the boot or glove box. Also the individual buttons on either side of the overhead light control unit don't work either.

The car does love to lock itself after a minute or so and I read that this IS related to the door locking module. ie, even though the central locking opens all the doors the car doesn't realise it has been unlocked and so locks itself again. Again, I don't think this is related to the interior light issue since you can't manually turn any of the lights on anyway with any of the switches which I know from owning other Mk4's you could always do regardless of any door lock module problem.

What I have done so far:

- Took the negative lead off the battery and ran a meter across it to establish the drain was approx 0.5A.

- Locked the drivers door lock latch with a screwdriver so the car thinks it's shut (read that the car should still be in a powered down 'sleep mode' if I do that) and then took every single fuse out 1 by 1 and metered across the points. One had a tiny drain, think it was 1 mA so nothing to see there. No reading on any of the others.

- Metered the ceiling light unit itself in every switch position. Seemed to imply that there was no current getting to the unit at all. Unplugged the lead inside the unit and did the same thing ... no power getting to it.

I am not an electrician, never tried to diagnose an electrical fault before so just been reading internet posts and trying to work it out. My conclusion is that there is probably a break in the wiring to this overhead light switch unit and that an exposed wire is shorting on something and draining the battery after 3 to 4 days ... BUT ... even if this were the case the glove box light doesn't come on either and neither does the boot light.

So ... on the basis it's a 4 motion and not covered by any Haynes Manual I am a bit stuck for ideas. I know that fuse 14 is the interior lights and central locking fuse but I find no drain on that when i meter the fuse 14 slot in the fuse box.

I am wondering if there is some sort of central electrical component in to which all the interior lights feed? ... and if so ... could a fault in this unit cause (a) all the interior lights to not work? and (b) a parasitic drain on the battery?

Been doing this since I bought the car 3 months ago. Didn't notice when I bought it in daylight and it only really came to light (scuse the pun) after a couple of weeks when it first sat for a couple of days idle and undriven / uncharged.

One other possibly useful bit of information. The battery terminals were loose when i bought the car (and i notice today half the fuses put in upside down) so presumably the guy I bought it off knew of the issue and had tried himself to unsuccessfully diagnose it, certainly someone has at some point had a whole load of the fuses out. Anyway ... as a result of the loose battery terminals, the day after I bought it this caused the indicator relay to trip out and coming out the next morning I noticed the indicators were illuminated permanently on the passenger side. Disconnecting the battery and reconnecting it (as well as rewiring the indicator bulb holder in the front headlight unit that had melted itself into a pulp!) solved that issue but I am just wondering whether that might have also tripped out or damaged some other electrical component related to the interior lights that I don't know about? Could just be a coincidence, like I say clearly at some point a whole load of the fuses have been taken out and put back in upside down.

Like I said, I am no electrician so I don't really know what I am doing here. Sure I can rewire a bulb holder or use a meter with a little internet help but as far as diagnosis goes I am pretty much clueless.

Any advice, suggestions / help or solution!! really appreciated! ... putting my car on to charge every night is a massive ball ache, plus ... I want to fix it and I just don't know what is the root cause.

Thanks

[Crasher]

We have had a few of those where the alternator takes a drain.