"rear control module" under driver's seat and water intrusion

[masraum]

Apparently, it's fairly common and/or well known that 997/987 have a module under the driver's (left) seat that controls things like tail lights, rear spoiler, etc..., and if/when water gets into the floor board, the module can malfunction. I have never been worried about it because at home and work, my car is in a garage, until we moved to our current house 3 years ago. For a long time I kept it under a cover, but since I'm driving more frequently, I am not putting the cover on every time I get home.

We got ~8.5" of rain over ~3 days earlier this week. Yesterday afternoon, I looked out the window and noticed that my brake lights were on and the spoiler was up. I didn't think about the water in the floorboard thing, but did some fiddling. Eventually over the next 2-3 hours, I realized that it was probably water in the floorboard, got the standing water sopped up with a towel, pulled the driver's seat and module, opened it up and dried it out and let it dry inside over night. I popped it back in this morning, and the brake lights seem to be working correctly, and the spoiler is working. WHen you pop the cover off the box you can see the circuit board. In one spot there was some schmutz in the gap between the case and bottom/back of the circuit board. With that wiped off and everything dry, the board looks OK. I think I got to it before any permanent damage was done. THere was hardly any water in the floorboard. I still have some work to do to ensure the padding under the carpet is dry, and to make sure that the drains are free flowing.

I plan/hope to keep the drains clear, so it hopefully, shouldn't be an issue. But, considering the possibilities, I feel like a layered solution that keeps the module drier wouldn't be a bad idea.

Does anyone know anything about keeping the module drier? It's too bad it wasn't designed like the old Ford control modules that were encased in some sort of glue/epoxy. I'm not sure how dry you can keep these things other than keeping water out of the floor boards since the wiring (3 large bundles plug in from the side.

[Shaun @ Tru6]

This is a common thing for 84-89 Targas and the DME under the driver's seat. Targa's leak pretty badly. Heavy rainh storm, lot of water in the car, DME dead. When I got another DME I mounted it to rubber isolators that stood about .75 inches above the floor with spacers.

[porsche tech]

996 and 986 BIG problem. Cowl drain clogs and fills up the cowl until it runs inside the car and soaks the floorboard. Back in the day we would have at least a couple of sets of carpet hanging on the back fence drying out at any given time. New immobilized unit, etc etc! IIRC Porsche even had a “recall” to stick another page in the owner’s manual stating that it was the customer’s responsibility to keep the drains clear. Best bet is to remove entirely the little grommet in the hole in the bottom of the cowl. Can’t remember if later models had that same pinchy grommet thing in the drain hole.

[masraum]

Originally Posted by porsche tech

996 and 986 BIG problem. Cowl drain clogs and fills up the cowl until it runs inside the car and soaks the floorboard. Back in the day we would have at least a couple of sets of carpet hanging on the back fence drying out at any given time. New immobilized unit, etc etc! IIRC Porsche even had a “recall” to stick another page in the owner’s manual stating that it was the customer’s responsibility to keep the drains clear. Best bet is to remove entirely the little grommet in the hole in the bottom of the cowl. Can’t remember if later models had that same pinchy grommet thing in the drain hole.

Ding, ding, ding!



I've got couple of videos queued up on YT to see if there are any with good visuals to make it easier for me to just go right to the spots that need checking/cleaning. Hopefully, those grommets are easy to remove.

[FPB111]

Ecu doctors waterproof case.
https://www.ecudoctors.com/products/waterproof-case-for-porsche-boxster-911-996-immobilizer-alarm-clu-computer

[masraum]

Originally Posted by FPB111

Ecu doctors waterproof case.
https://www.ecudoctors.com/products/waterproof-case-for-porsche-boxster-911-996-immobilizer-alarm-clu-computer

Yep, I had found that and was pretty excited. Unfortunately, it's only for 986/996. It isn't helpful with the 987/997. The 987/997 module is quite differently shaped with 3 separate plugs.

986


987

[john70t]

Locating crucial electronics on the floor...
It's like building entire cities on swamp land and former lakes below sea level.

[masraum]

Originally Posted by john70t

Locating crucial electronics on the floor...
It's like building entire cities on swamp land and former lakes below sea level.

I hear the bases of active volcanoes are also great places to build homes, towns, etc...

Actually, it probably wouldn't be that bad if they built them like the old ford ignition modules...

[porsche tech]

Those Immobilizer ECU’s and key heads caused a myriad of problems, even when they weren’t flooded. We had one guy who wanted a new key and turned out his USA car had a European immobilizer. There are numerous MHz versions of the USA key heads and none matched up with the European ECU. Probably not getting any less complicated these days!

[masraum]

Originally Posted by porsche tech

Those Immobilizer ECU’s and key heads caused a myriad of problems, even when they weren’t flooded. We had one guy who wanted a new key and turned out his USA car had a European immobilizer. There are numerous MHz versions of the USA key heads and none matched up with the European ECU. Probably not getting any less complicated these days!

I don't know if my 987 has the immobilizer under the seat. I do know that the module under my seat controls things like the spoiler, tail lights and power top. Hopefully, the immobilizer is somewhere else.

[Zeke]

Boxsters don't do well with the canvas top part that is below the body line. Essentially it shouldn't get wet. They are not rain cars, but how can one keep it out of the rain 100%.

Don't drive it. That's why my wife's 2000 has 63,000 miles 20,000 of which were clocked during 2000 and 2001.

[masraum]

I have had the hard top on my car for about 3 years now, but that doesn't stop rain from getting to where the drains are.

The good news is that the only place that I seem to have a leak is on the driver's side so I don't have to deal with 2 separate spots that are currently soggy. I guess that's also the bad news since that's where the module is, but it allowed me to discover the problem before it was a much bigger problem without costing me a ton of money.

I'm going to get a set of the drain screens to help.


I'm also going to get a trombone brush to ensure that the drains are clean.

[john70t]

Might consider a weak anti-bio agent as well.
Bleach would hurt plastic. Wet-n-Forget is slow acting for green mildew and used when dry.
Not sure about other chemicals.

[masraum]

Originally Posted by john70t

Might consider a weak anti-bio agent as well.
Bleach would hurt plastic. Wet-n-Forget is slow acting for green mildew and used when dry.
Not sure about other chemicals.

Good call, thanks. I'll have to check that stuff out.

[john70t]

Don't use W-n-F. Sorry. Probably wrong application. That's for mildew/moss on dry wood and other.

I forgot there are chems made for humidifiers which are pretty strong and stinky but presumably plastic safe. Just a spoonful or less in a 2 gal tank needed.

[masraum]

Originally Posted by john70t

Don't use W-n-F. Sorry. Probably wrong application. That's for mildew/moss on dry wood and other.

I forgot there are chems made for humidifiers which are pretty strong and stinky but presumably plastic safe. Just a spoonful or less in a 2 gal tank needed.

will do a search, thanks

[look 171]

Originally Posted by porsche tech

996 and 986 BIG problem. Cowl drain clogs and fills up the cowl until it runs inside the car and soaks the floorboard. Back in the day we would have at least a couple of sets of carpet hanging on the back fence drying out at any given time. New immobilized unit, etc etc! IIRC Porsche even had a “recall” to stick another page in the owner’s manual stating that it was the customer’s responsibility to keep the drains clear. Best bet is to remove entirely the little grommet in the hole in the bottom of the cowl. Can’t remember if later models had that same pinchy grommet thing in the drain hole.

Where is that located exactly. I have never clean mine now reading this, it looks like a must do. 2010 Cayman S maybe very similar to Steve's Boxser?

[porsche tech]

Bottom of the front cowl below the windshield…not particularly easy to get at.

[look 171]

Originally Posted by porsche tech

Bottom of the front cowl below the windshield…not particularly easy to get at.

Looks like that isn't something that can be done in a couple hours? It requires removal of a bunch of parts jsut to get at it? I wonder is I can just take something like a long needle nose pliers to get it out? There are 4 total?

Thanks

[porsche tech]

Mind you, I’ve been retired for 12 years (and I’m a geezer) but I seem to remember the one in the center of the cowl could be knocked through to the floor with a long fat screw driver. IIRC it could be done without removing a lot of stuff.