I had the same problem but managed to find the source of the leak. I first removed the roof trim but there is no entry point into the car along that so put it back on. Then through using a hose and isolating various areas I was able to find a vent under the rear bumper that was letting water in under its seal.
Removing the bumper a bit fiddly but doing able. See video link for how.
Then once that is done you can either replace or seal up the vent. I sealed up one but the flaps on the other had gone so got a replacement for £10 from a local Hyundai garage. You can also get them on eBay for around £15.
Get one out is a bit tricky but there are two small gaps in the top where you can put screwdrivers in to press a bendy bit and then with a bit of force lever the vent out.
I hope all that helps!
read more and respond »Posted 3 years ago by Callum in UK Do-It-Yourself Forum
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