Drain routes

[Ade B]

Hi there, anyone know where I can find a diagram showing all the drain holes/routes on a 1991 300CE 24V?

Wet carpet to offside rear passenger footwell - rest of car is dry... looking at other threads, it could be a leak anywhere, so would like to go round all the drains and make sure that they are clear and not perished.

Thanks

Ade