Bizzare Cabrio issue- help needed!

Hi all! thanks for creating this forum, I�ve read for years and learned tons from many on here this is my 3rd 996, and this one is close to perfect. one thing I can�t figure out seems so simple but is driving me nuts. Top will only open and close via key in the door method. The switch/button is not working. never did on this one. I�ve purchased new and used switches, followed the wires and looked for possible loose connections/damage. Ive changed and refilled the fluid- (opens and closes very smoothly) Neutral, parking brake, open and closed trunk and engine bay solidly. push the button and.. nothing. Not even a relay click. question, is there a light that goes on when the drunk or engine lid is open? if there is, I don�t have a light� only for the spoiler and convertible� anyway- I�m losing enough hair, I don�t have much left to pull out over this. if anyone has dealt with this before, I would very much appreciate some insight on a solution. y apologies in advance if this has already been addressed in another thread- I searched and could�t seem to find one that addressed this issue. thanks In advance!

I have a 2000 Cab, I'm not sure what the key in door method is? in mine I get in and either turn the ignition on, or start the car. Then press the top button and it all goes. This is not working on your car?

Your problem is the E-Brake switch .......( I have seen it 100+ times) There is a micro switch under the E-Brake mechanism that tells the system that the car is stationary ( safety feature) and allows the top to be opened / closed...... The way to tell if the switch is working is to lift the E-Brake handle and the little red "brake light" in the instrument cluster should illuminate....... If this little red light doesn't illuminate, it means your E-Brake switch is faulty.... to replace it you will need to remove/lift the console..

So I check the e-brake. light goes on and off when engaged. So it�s not the micro switch. as for the key method. if you put the key in the drivers door and hold in lock position it closes, same for holding in unlock position. This is the only way I can open and close my top. the button on the dash does not have an effect. I have also replaced this part, still no effect. at a loss here�

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I'm having trouble grokking this. Are you saying that the handbrake must be pulled in order to raise and lower the top? Or does the switch have some sort of motion sensing capabilities?

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Yes, the hand brake must be engaged. At least one click and the brake light goes on. That's just for operating with the dash button. The brake doesn't need to be on to use the key in the door to open/close the top. There is a speed sensor component to the dash switch as well. For MY 2000 and earlier the speed must be zero for the top to operate, unless you do the simple mod to cut the speed wire. I believe starting with MY 2001 the top could be raised while moving.

I still can�t figure this out� Anyone have any ideas? it�s not the ebrake micro switch Again, top opens and closes flawlessly using the key in the door� just can�t get it to work from the dash button.🤷🤷🤷🤷

Check fuses B1 B5 D3 and E1 ( if you have a 996.2) ..they all go to the convertible top module..if not that then.... ...Sounds like you need a PIWIS or someone with a PIWIS to have a look at this... ( and a wiring diagram for your model year).. PIWIS has a wonderful amount of info on convertible top functions....can show all sensor/potentiometer values/positions, switch functions on/off , can actuate individual components/electric motors, and of course calibrate the whole convertible top mechanism.... Personally I would chose the PIWIS route, but if you want to proceed the hard way then get a wiring diagram for your model and test continuity of all wiring from control unit to component, starting with the dash switch wiring, until you find a broken wire or confirm they are all good....if you find a broken wire fix it and re-test...

That�s such an awesome reply and advice! thank you very much, now I guess my next inquiry on opinions� should I invest in a PIWIS for my 996.1 (I think I�ll also need an adapter) to mess around with? Or do you think I should leave it to the professionals and take into an Indy or Porsche service center? can I mess things up myself? Like beyond repair?

I just encountered a similar issue with the top not responding to the dash button. In my case it was fuse B5 (7.5 amp) which is also used for the side view mirror motors. If you haven't checked it that's the first place I'd go. I've had an ongoing issue with that fuse blowing when I try to adjust the passenger side mirror, but I guess I never tried operating the top before replacing the fuse. My issue is likely with the switch or a short in the wires as the mirror will drop automatically in reverse without issue. It only fails when I try to adjust it with the switch.

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If the roof works off the key in the door, it�s likely an input issue to the controller. See if you can find the wiring diagrams for your year of car and trace the path on the diagram from the switch to the controller and from the switch to its power source/ground. Then use a multimeter on the wires to check continuity. PIWIS or durametric might show a fault. Check the connector on the controller for contamination too.

Try the simplest test first - See if your side mirrors can be adjusted using the switch. If not, then fuse B5 is blown which would also cause the dashboard convertible top button not to work.