This was posted awhile ago and I made a copy (sans pictures so you have to work that out for yourself). I never tried it but figured it would be useful someday. Credit goes entirely to the original poster (misterturbo). Hope this helps.

 

Thanks, I did see that when I first searched but I don't have a compressor (or a long lance) and as it's predicted to rain constantly for the next 2 weeks I caved in and took it to my local Porsche dealer this morning! They will dry it out, sort the electrics and valet it to get rid of the wet dog smell ...

 

Yeah, I've also used misterturbo's approach. I don't have a compressor either but I have our independent take care of it for me. If there's debris near the upper opening you can clear it using a claw retriever but for the debris in the drain tube you really need to blast with air or vacuum.

The drains are visible from above without removing anything though access may be easier with the rubber part removed. I test the drain tubes by pouring water into the opening. I usually have to move a rubber hose or rubber covered wires (not sure which it is) with something like a long screwdriver to get it out of the way.

You definitely want to keep these cleared. The convertible top module is on the floor pan under the driver's seat and the convertible top drains will overflow right into the floor pans in the passenger cabin. Our SmartTop module ended up fried because of this. If I recall correctly, there may be some electronics on the passenger side as well.

 

Just in case it's helpful to know what the drain plugs on the exterior look like, this is the view when I removed the rocker panels on my 982. I'm assuming that it is similar enough as the tops are the same between the 981 and 982...




The lower one way drain plug and hose was completely filled with with pine needles, acorn bits, and tons more organic materials. I suspect that multiple good blasts from an air compressor would have cleaned these out on my car, I just didn't know how to access the drain from the topside. I do now, thank you!
Using a vacuum probably won't work very well due to the one way drain plugs.

 

Yes, please remember to do this. My was clogged, water got into the passenger's seat without me knowing until there was an error on the parking sensors. The electronic under the passenger's seat was messed up. Cost around $700 through my independent mechanic. Dealer wanted $2000k just to get the water out.

This is the reason why during fall and spring, I cover the soft top so stuff don't get built up around the back edge of the top.