went to change my bk number plate bulb today and when i took it out the unit in side was all rusted and water in side any idea how this could have happened ?

VAG clearly haven't sacked the engineer who designed all the water leaks in the Mk1 Superb and have let him loose on the next one.

At least your vehicle should be under guarantee, but if this is a typical VAG design stupidity, Toyota have nothing to fear.

Note to VAG engineers: Cars get completely soaked in water under pressure - top and bottom. If you can't make the damned thing watertight, fit drain holes. Drain holes have to be at the bottom because of a phenomenon known as gravity. Design them so they don't get blocked by everyday items such as leaves. Finally, when you've failed in all of this, don't put £500's of electronics on the floor where gravity will ensure that it gets wet.

End of rant.

rotodiesel.

I had to replace one of my number plate bulbs recently also. I agree that the area looks prone to corrosion.

I think that VAG bought in a cheap batch of bulbs recently because since I have replaced mine I have seen no end of Skoda, VW and Audi's with blown bulbs. When I went to buy my replacement I bought 2 just in case!!