Hi all. There is some air gets into the purple area underneath the windshield of the rain sensor of my X, it results in malfunction of the rain sensor. Here is the question:

1, is there anyway to fix it without replacing the windshield?
2, if replacing the windshield is the only way to fix it, may I just upgrade my rain sensor to rain and light sensor (the newer version)?
3, I have the headlight switch with auto-light-on function in hand, I also have the rain and light sensor in hand, what else do I need to upgrade my rain sensor to rain and light sensor?
4, do I have to re-code any thing?

Thanks for help!

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--2004 E53 X5 4.8is - ECE version; right hand drive; Located in Hong Kong; ext. black sapphire metallic; int. leather black; adaptive dynamic bi-xenon headlights; 16:9 onboard monitor w/o navigation; 20" genuine BMW Y-spoke 214 wheels with Bridgestone Dueler H/P Sport tires; Int. rear view mirror w/ compass.