Only water ingress problem for me on my D3 has been the rear nearside inner light.
This shows in two ways:-
- Occasionally on applying the brake we get a Brake Light Blown fault.
- Looking closely at the rear offside lights when locking/unlocking the tail light LEDs on both units flash very dimly for a few seconds.
Taking the offending light unit out, drying it thoroughly resolves the problem until a jetwash hits it, or some very heavy rain. I have vaselined the rubber seal but I think the main problem is the cracks in the reverse light lens area. I was hoping that the dual plastic there would stop water getting in, but maybe not.
I'll have to find time to have another go at it.
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Ray at Wigan Pier
2014 A8L D4 4.0TFSI Gold (Sticker says "Beige") Can't leave you in a black smoke cloud anymore..
In progress, Nothing left to do.
Gone 2004 A8 D3 3.0 TDI. Ebony Pearl Black (with little bits of other colours and glitter)