Your answer: Had my c3 for nearly 2 years, I dread the light bulbs going in the headlights, condensates up every time that back cover is removed. I remove the excess water, using a turkey baster, to vacuum the water out, then dry off using kitchen roll to soak up any excess, then put clear sealant around the casing, which does come off, for next time. Then sit in the car with the engine running for 15 minutes with all the lights on, the heat removes any excess moisture. Good luck!!
Jason Hamer
July 2012