When I swapped my own switch module to test before shipping I decided to prevent the problem from ever happening on my car: I broke the bottom corner off so water can't possibly puddle inside. I was going to drill a clean hole but decided to just break off the corner with a big scissors. (Too difficult to drill without disassembly)

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)