if your ML has a sunroof the drain tubes run down both the passenger and drivers side footwells i have seen these where they have come off. would be worth a quick check.
A common problem on the W163. The sunroof drain pipes that run from the sunroof down either side of the car snaking under the A-pillar and exiting the car via a rubber grommet which it connects onto are located in the footwells to drain water via the wheel wells.
This grommet has a pipe which also connects to it on the outside which hangs behind the wheel well shield and water drains via this pipe. So water drains via sunroof along drain pipe in A pillar then into grommet onto the last pipe hanging on the outside. This pipe is quite long and flaps around as you drive and over time wobbles the grommet and causes the pipe on the inside to pop out of the grommet leaving all water drained from the sunroof inside the footwell rather out of the car!
The driver side is easy enough to get to. Clean the muck stuck in the grommet and use a cable tie on the inside to ensure the pipe does not become free again. Also reducing the length of the hanging pipe on the outside to reduce the flapping and any more problems.
Passenger side is very hard to get to from the inside. The blower motor housing is fixed in there and i don't think it can be removed without removing the dash. It can be done though.
