Battery warning light dim when keys out of ignition

[CabbageGT]

Hi

So I've recently put back together my 1.8n/a which had a million problems before the rebuild and still has some issues now.

I started it up for the first time last week to get some oil pressure and circulation, when I turned her off, the battery light came back on and then started to fade away, keys in my hand!!!

Over the weekend the battery has been drained flat, and my only explanation is that the regulator in the alternator has gone kaput. Sent it off for analysis and low and behold it's fecked.

It's been refurbished and retested positive, refitted today and I have the same issue. If I unplug the signal lead to the alternator the light goes out completely. I've noticed this has cause other controls to remain active without the key. Lights, windows, sunroof.

Lastly, the light occasionally flickers as if there is a short somewhere. Something in the boot makes a ticking sound every flicker of the warning light. But I can't seem to be of any influence to the issue other than unplugging the alternator fly lead.

Any ideas,
All help appreciated.

 

[RGL]

I don't have much input to add but the window switch lights and probably the sunroof (don't know for sure, as I don't have one) stay on even after you take the key out. Atleast on mine they do, I think the window switch lights switch off after I've opened (& closed?) the door. Or possibly after some pre-determined time period.

EDIT:
Have you checked it or scanned with VCDS/VAG-COM? These type of things might often throw up a code which can make the search easier.

 

[CabbageGT]

I'll check this tomorrow, is there some controller or timer which allows power to run to certain things such as radio for a short period of time... Sounds like something I had to bypass on a Peugeot once, but I put that down to French wiring. I'd be disappointed with this being German. Plus it'd be a bit advanced for a 96plate. I'll get someone to tug on every wire in sight while I sit and watch to see if the battery light goes out.

 

[RGL]

I have no idea how the system works or whether it's normal, but all I know is that my window switch lights go off after I've opened and closed the door or after a period of time. I would check mine so I could be more precise, but it's currently sitting sumpless (waiting on a new one) with the battery detached.

Mine is a '97 plate and the same engine as yours, so unless mine happens to also have an electrical issue (hey you never know with these oldies ), then I think you have the same thing.

 

[CabbageGT]

I'll be looking to the fuel pump relay, also checking that this issue isn't what cause the regulator to become crappy in the alternator.... That would be a pain if it has to be repaired a second time.