Originally Posted by seattle

yesterday, found water (again) in passenger side rear compartment. A month or more ago, tailgate module fried because of water there. At that time, I thought water got in there through side vents after pressure washing.

I was occasionally checking that area over coming weeks and things stayed dry. Yesterday, after a week of heavy rains (Seattle), checked again - water!

Luckily, I got to it while it was still raining and I observed water dripping from somewhere above. Traced it to the wiring boot.

Applied generous amount of silicone and reassembled.

It is a bad design, really. The opening for the wire on the body should have elevated edges. That alone would have prevented most water without any special seal. Instead, it is flat (see OP's pics) and we have to rely on rubber to stop the water. That doesn't quite work.

Also, observed little plastic flap of the sunroof drain (right next to the wiring boot) was pushed in too deep into the tube and not opening properly. Took it out, cleaned and pushed it in properly - now opens easily. That had a risk of flooding from sunroof.