I don't know if your car has both front and rear sunroof drains. The front drains usually run down the A-pillar to the front wheel well; a rear drain would probably end up in the rear wheel well, which might explain your problem.

There have been many discussions on this forum of various ways to clean out a clogged drain. Some people advocate use of the plastic line that string trimmers use, others like a small drain snake that Harbor Freight sells.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970