I am getting significant water leaking in the driver side rear footwell. It is coming from underneath the rear seat. Could the sunroof drain be broken? clogged? How can I check or fix?

Randy
84 300SD
85 300SD

 

There is a good chance the water is coming from the drains in the front, near the fire wall. If those get clogged I believe that is where you will see the water. If I'm not mistaken, if the sunroof drains are clogged, you'll see it either on the headboard, around the back window edges or in the trunk.

 

I would check the drain for the air conditioner evaporator. I believe it drains thru the floor board on the drivers side front, about even with the shifter. I think you might need to remove the cover for the console.

If it's leaking from under the back seat, I'd look for a drain for the rear window. I'm not real sure about that location.