Cali roof/sunroof leak

[2002mcs]

I traced an interior water leak to the left front drain of my Cali roof. When I pour water directly into the drain the water will enter the interior from the bottom of the dash above the hood release. I removed the lower dash panel but could not see the source of the flow. This is a steady flow with no water reaching the ground via the drain.

I did a search on this but could not find a discussion of this specific leak source. Is there a rubber tube somewhere in the dash that channels the water to the sill drain that can become disconnected? Could the drain be clogged downsteam and is backing up into the dash?

Before I try to blow the drain free with compressed air I would like to understand the construction of the drain.

Any suggestions would be appreciated. Thanks