Audi A5 Cabriolet Battery Drain

[Barry1394]

My first post, and it's a solution so I hope it helps someone.

Have a 2009 Audi A5 Carbriolet which suddenly had a total battery drain. Only other clue was the high-level brake light on the boot was on all the time (when the battery was charged).

Have seen lots of threads here covering issues similar to this, but none of them solved the problem. The main issue was related to the fact it was a soft-top which had leaked!

Had removed every single fuse (individually) to try and isolate the problem without success. There are 4 fuse boards in the A5 (5 if you include the ones on Terminal 30 on the battery).

So a fully charged battery was giving 5 amps of drain after all the circuits had shutdown. It's over 12 amps before that happens.

Discovered that moving the loom near the fuse-board changed the current drawn by around 1-2 amps. On unwrapping back a large section of cloth on the loom, discovered that Audi seem to be joining high current cables within the loom. Two of the high current connections appeared eroded. Then I noticed a green copper deposit on the chassis towards the rear of the car. So it looks like the copper was electroplating onto the chassis via the damp in the loom and water held in the sound proofing (a sponge!).

So, I had to re-join the connections. On the basis the existing method used didn't work I potted them in something non-conductive and ensured they pointed up so that moisture could not drop down into them.

This all seems to have worked (see pictures).

Hope this helps someone as it took a really long time to get to the bottom of it.


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[jdragon]

Thanks for sharing