What the front drains look like clogged from being parked near trees that shed.
The front drains are the black grommets just to the left of the battery under the exposed colored wiring. There is a similar one on the other side of the battery.
Note that the battery has been removed and that the rubber grommet on the driver's side drain hole has also been removed (but not intentionally). I have to fish it out from underneath, so be careful, it's easy to push it through to never-never land.
Be VERY VERY careful to detect any water that is ending up under your seats. Correct the problem with any of the rear drains ASAP.
is a central alarm control module under one of the seats (left seat on
U.S. cars, not sure if it's under the right seat on UK cars), but you
can't miss it. It's a large square metal box directly under the seat.
If it gets flooded, you are looking at about a $2,000 repair. It also
controls the ignition and a number of other functions. When it gets
wet, you can sometimes resurrect it by opening it up and drying it out
but it's much better to prevent it from happening. If this happens, unplug the
battery and get fans and or a hair dryer to dry the area off, then see
if things work again. You may have to remove the seats and clean the
controller with isopropal alcohol.
Removing the seat is a very simple matter. There are four torx bolts holding down each seat, but you can get them off with a 10mm small drive (1/4 inch) regular socket if you are careful.
To take the seat completely out, you will have to disconnect the large connector under the seat. DO NOT disconnect that connector with the ignition on or turn the ignition on while the connector is disconnected or you will set off your airbag light. That can then only be reset with a PST2, PIWIS or Durametric unit. There is the possibility of setting the seat on the ground next to the car without disconnecting the connector, but it does get in the way a little. If you go that route, you don't have to worry about the airbag light.
As far as diagnosing the water leak problem, fill a quart jar with water and put a pan on the ground just forward of each rear wheel to catch the water as you pour it down each drain hole. The drains exit just forward of the rear wheels. If you have a full quart after it all drains out, your problem lies elsewhere than a clogged drain. Be sure to check each foam liner drain tray for any rips or tears, especially in the area directly beneath the V-levers that operate the pushrods of the convertible top. If you ever had one of those pushrods break and the V-lever rotated with the broken pushrod dangling, it will invariably cause a tear in the drain tray that will in turn cause water to leak into the passenger compartment.
You can buy the drain trays separate from Porsche.
Porsche calls them "water drip pan" .
The part numbers are as follows:
986 561 805 03 (Left side)
986 561 806 03 (Right side).
They each list for $75.76, but you should be able to get them for less from Sunset Imports.
Replacement is straightforward but a little time consuming. The most involved part is the removal of the three bolts (and either one or two phillips head screws) that hold the base of the convertible top frame onto the car. You will also have to remove the 19mm bolt that holds the V-lever onto the convertible top transmission, then the V-lever itself. Then there are a couple of large plastic "screws" at the rear of the convertible top well on each side.
If you don't want to spend the $$ and the tears are not too bad, you can repair the drain trays with black urethane sealant.
Again, whatever you decide, be very careful about the water and the alarm control unit under the seat."
The front drains, if clogged, allow water into the front trunk which can rust the floor pan.