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Discussion Starter #1
I've had a 57 plate 2.5 TDI since November, with a view to converting it to a camper. Everything seemed fine until I had to drive it thru floods in December. Soon after, the alarm started sounding intermittently, the central locking stopped working, and the battery lost its charge. The local garage checked the battery, which was dead. I've recently bought a new battery and replaced the corroded red and blue wires under the drivers seat. This worked for about a week or so, but then the alarm started going off again and the battery has drained again. I've had a look in the consumer unit under the drivers seat and this seems fine, but something must be draining the battery while the van is sitting on the drive. Any ideas please?
 

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alternator is the favourite. do a current drain check from the battery, then disconnect alternator carefully, if a reduction in drain thats your trouble. if not start pulling fuses till you find it.
 

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You will need a multimeter with 10 amp DC current scale. Disconnect negative cable from battery and connect the meter between the battery and the negative cable. Make sure all doors are closed and wait 30 seconds for true reading. Should be less than 0.1 amps.
 

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Discussion Starter #9
Thanks for help. My multimeter on the 10Amp setting reads 0.05 with all doors shut etc. I've checked the fuses under the ash tray and the reading goes down to 0.04 when I take out number 3 (from the top fuses), and goes to 0.03 when I take out number 11 (from the bottom fuses). These seem to correspond with the Multifunction Control Module 1 and the Central Locking respectively, although I'm certain of this. Is one of these the clock, mileometer etc? Also, not checked the alternator yet as not quite sure where it is or how to access it...any ideas please? Thanks.
 

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Just a quick comment from me ,i had a similar problem and it was my sliding door ,the interior light in the rear was coming on and off all on its own like the door was being opened .
All i have done is set my interior lights to the off position instead of the open door setting .

Worth a test i suppose
 

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Discussion Starter #14
My local garage have had the van for some other work, but have also tried to find the battery drain. They've checked the alternator, which is charging to 13.6v They said this is slightly low but not desperate. They have had another battery on the vehicle which was also drained within a day or so. Their electrics guy could also find no drain on it when the engine was off (as I couldn't). IS IT POSSIBLE that the lack of the plastic battery cover could be shorting the battery slightly while the bonnet is down, and thus not noticed while we check it with the bonnet up? It seems like a long shot to me, but does anyone know whether this is possible?
 

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No Kev, that's not possible. What is more likely is that there is an issue with one of the ECUs turning something on sometime after you leave the vehicle. Has the van been scanned?
 

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Discussion Starter #16
My local garage have had it on their diagnostics but admitted that they don't have access to all the vw fault codes. Is it something that a vw garage would have to do?
 

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Discussion Starter #18
The latest on my battery drain: I've just done the fuse pulling test again, but this time noticed that the normal reading of 0.06 amps increased to 0.26 when I opened either the sliding door or the passenger door (but NOT the driver door). This happened with the interior lights off. The reading would stay at 0.26 even when the door was then shut. The fuse which brings it back down to 0.06 is no.3 under the dashboard, which seems to relate to the onboard control unit J519. So I think I've found the culprit...any ideas on how to rectify it? By the way, thanks for all your help so far, I can almost see a light at the end of the tunnel!!
 

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I am no auto electrical expert, but we have had a few vans where the owners have reported a drain over a week or 2. Whenever we have tested a T5 with a meter between the positive terminal and the battery clamp, the readings have just varied and fluctuated all the time, indicating that there are various signals going back and forth to the ecu etc.
I have not noticed this on other vehicles (admitedly older), but this seems to be the same on the few T5's where we have done this.
I know I wouldnt like to leave mine for 3 weeks without driving it, but a week or 2 is never a problem.
 

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The latest on my battery drain: I've just done the fuse pulling test again, but this time noticed that the normal reading of 0.06 amps increased to 0.26 when I opened either the sliding door or the passenger door (but NOT the driver door). This happened with the interior lights off. The reading would stay at 0.26 even when the door was then shut. The fuse which brings it back down to 0.06 is no.3 under the dashboard, which seems to relate to the onboard control unit J519. So I think I've found the culprit...any ideas on how to rectify it? By the way, thanks for all your help so far, I can almost see a light at the end of the tunnel!!
Don't be fooled by this. If you waited longer, say 10 minutes, you would find the reading drop again. If you are satisfied that your battery is 100% then go ahead and change the J519. As you have no obvious drain (0.06) you would have to assume that there could be something wrong with sleeper circuits.
 
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