Hi Audi fans,

I am a huge Audi fan myself, have three of them that the family drives, all aging gracefully. Though, on our A4 2010 B8 Premium there are a couple of issues that I am not sure if they are related to each other.

There is a parasitic battery drain which starts when I lock the door with the dome light switch set in the neutral position.
I've monitored the shutdown sequence with an Ohm meter, listening to the relays clicking, while watching the amp usage go down as the car shuts down things and goes into lock state and hibernation.
But, when the dome light is in the neutral positions (i.e. dome lights come on when the doors is opened), when I lock the car (with the trunk latch locked) the sequence gets all the way to 0.3 AMPs and then wakes up again, and jumps to 6A. I hear the amp click, the parking brake light comes on and then this sequence repeats eventually draining the battery.

Some other things I have done:
* I had thought it was my tailgate exterior button because that never did work (I purchased the car 6 years ago, but was never an issue as we used the key). I removed the tailgate switch from the circuit and the problem still occurs.
* I have an AutoPhix 7610 Multi scanner, not a VCDS, and I am able to monitor voltage and state on each door. All doors seem to be fine and I do not see errors from those control modules. I do see an error from the Radio, but the radio seems to work fine. That error is 000003 Control Module.
* I have tested the alarm system and it works fine.
* The dome light behaves as it should do, shutting down after a minute when you close the door, or after several seconds if you lock the door with the remote

I have some questions:
1. What other things can I check?
2. What is the shutdown sequence for the car when you lock the door. Is that documented anywhere?
3. What module does the interior dome light connect to that could be effecting the the shutdown sequence?
4. Could the error from the Radio be causing this problem?
5. Does anyone have a schematic for this they could share?
6. For the Trunk latch exterior switch (the button with the camera), how can I test the latch to see if that is faulty or if it is the wire? I'd like to fix that too. The latch itself unlocks with the remote.

Thanks and appreciate any help here. I've poured a good 10 hours into this already.

Alan

 

Wow, sometimes our Audis are just more complicated than they have to be. You have put a lot of work into this, but are you sure it is related to the dome light. I read your post twice, and I see nothing about testing it with the dome light in the "off" position so it does not turn on at all. If that solves it, maybe live w/o the interior light. Otherwise good luck finding the source problem - really.