Roadster AC Drain
The pipe that transports condensed vapour out of the AC box to the outside of the car can fail to do so
This fault will cause wet carpets in either or both of the footwells. It's fairly common to
find that these drains aren't correctly seated so the water drips into the footwells.
Pull back the carpet and remove the polystyrene footwell block, you can now see the AC drain.
It's common for the bottom of the drain to be out of its assigned hole. You can see on the picture that the dust around the exit to the drain has been washed away, showing the presence of water.
Simply insert the drain back into the hole in the floor.
Don't forget to check the other side too
While you are there it would be wise to massage the pipe to ensure there are no blockages.
Also, check the top of the pipe as they have been known to split where they join the box.
These don't just drain condensed water from the air conditioning, they drain any water from the cabin air inlet system. Rain and an overflowing air inlet tray can allow water into the system.
It has been brought to my attention by weasle1uk that these pipes can perish,
split, or become old and loose so it is worth a quick check. Obviously, if it it's
split or poorly sealed at the top, water will get out and drip into the car.
What he did was to add a collar to the existing pipe and hold it in place with a pipe clip.
Replacements are available from smart.
Smart part number: Q0009982V004000000 (thanks weasle1uk).