TL/DR - How do you remove the rear C-pillar curtain airbags? I need to check the sunroof drains to find a leak...

I've been having an issue with my 2001 LS430 retaining water in the rear cabin of the car. Every time it rains the rear left and right floor mats become soaked along with both R/L C-pillar airbags. I suspected the gutters were clogged and rusted through, but after taking my car to a body shop for advice they said to check the rear wheel wells to see if the drains are clogged, clean them out, and that I should also check around the airbag area for the drains to see if they're leaking or blocked.

Problem is, I can't find anything on how to remove the rear C-pillar airbags without having 99.9% of the search come up with, "MUH *AIRBAG* SUSPENTION BROOK WAAT DO?!?1/!?" or "EBAY - *C-PILLAR* TRIM PIECES $$$$"

 

Do these help?

 

I would try and lance out the drain slits first. It's easy to do and may fix your problem. Lexus has a design where the drain tubes travel down to the rocker panels which then fill up with water and drain below. Don't ask me why they don't just extend the tubes all the way to the bottom of the car. The rocker panels can fill up with crud and the tiny slit drains under the car won't release the water. Get under the rear of your car and locate the drain slits as in the picture below. Take a stiff weed eater line and push up into them to see if any water from the cavity releases. Hopefully that will work for you.