2008 S550 ... 221.186 70K miles

EPC schematic for this vehicle's sunroof shows the vehicle to be equipped with two rear sunroof drain hoses (221 782 01 96) running from the sunroof frame and down their respective C-pillars.

Anyone know where these drain hoses exit and how to access them?

I'm assuming they run down the rear of the wheel arch... not in front, so the rear seat back and cushion would not require removal. If to the rear, can the hoses be visualized by removing the inner trunk liner panels?

Currently have experienced a sudden onset of the left rear passenger footwell and the trunk's spare wheel cavity filling with water every time it rains.

Perhaps this image will help...

Left rear drain is item #610

Attached Thumbnails

 

Checking the drains is as simple as opening the roof and pouring a cup of water into the trough. You should see it coming out within a few seconds.

ILUVMILS - your answer assumes the drain is patent and properly routed.

In this case the drain hose was clogged and fluid was incapable of exiting the vehicle. Headliner was subsequently partially dropped and the drain hose unclogged and flushed; after doing so, water could be observed exiting via a drain located aft of the rear tire.