During heavy rain, drops of water start coming through the interior light buttons. All the buttons still work except for the passenger's side light, which didn't work when we bought it from its last owner, though I suspect that the bulb is just dead. I'm not exactly sure how and where water is getting in, does anyone have any similar issues in the past?

 

The most like cause is the sun roof weather stripping. Check that the sun roof is seated against the seal. Try tilting it and check for tears and slide it open and check for tears.

 

Perhaps?

https://www.jaguarforums.com/forum/x...f-leak-179127/

Particularly a drain pipe of the drain.

 

I'd say the sunroof drains are plugged, a problem common to many cars. Search internet for tips on how to correct.

 

The seal looked good so I read through that thread and cleaned out the drains with pressurized air and Lysol. Nothing seemed to seep in through the cabin when I dumped water into them or when it rained, so I'm going to assume I'm good from here. Thanks all!