I noticed water dripping behind the glovebox and onto the front passenger foot well carpet. I disassembled the interior and to my confusion, the cabin filter and blower motor were both dry. I tested the sunroof drains but they drained freely and did not cause any water to leak into the interior.
Eventually, I figured out that water was leaking below the lower windshield trim (#30674707, 2a in following diagram) and dripping directly into the HVAC inlet and pooling on the blower motor housing:
Reseach suggests this is a common issue after windshield replacements; however, my windshield was replaced many years ago so it’s possible that the trim simply leaks overtime? Here is the lower windshield trim’s profile (the windshield goes into the larger channel, and the wiper cowl goes into the smaller channel):
As a fix, you can retrofit a splash guard (#8693157) from the XC90 to prevent water from dripping into the air inlet. You could also get creative and use anything that will cover the inlet without restricting air flow.
To gain access to the rain tray area, you’ll have to remove the wiper cowl which means you’ll likely have to pull seized wiper arms. If you don’t have a puller, this trick with locking pliers worked perfectly for me:
Before installing the splash guard, you can also check the integrity of the gasket on the air inlet duct (#30643490, #18 in following diagram) and reseal or replace if necessary (mine was fine):
You’ll have to find a creative way to install the XC90 splash guard (#8693157) as our cars have nothing for it to clip to. It sort of tucks in by the corner of the windshield but is far from secure. I used butyl tape (ie 3M Window Weld ribbon sealer) and adhered it to the bodywork under the windshield, and the bottom inside edge of the splash guard rests against the HVAC inlet duct. This will make a lot more sense once you see the area yourself. Not sure if this is the best method and am open to other ideas.
Update: The 3M Window Weld ribbon sealer failed after a few months, likely due to cold weather and excessive movement?
I ended up finding a better way to mount the splash guard – if you trim the tabs off, you are able to fit the splash guard into groove under the windshield seal and it almost holds itself in:
I ended up applying a bead Permatex clear silicone adhesive sealant above the silver mark to secure the splash guard in place:
Let’s see how long this will hold.