Swallowtail

Hi,

something is wrong with the spoiler on my 964. The spoiler goes in and out depending on speed as it should - however the manual switch does not work. The switch itself is not the problem - first thing i checked.

If someone could help me with the wiring diagram I’m confident I could find the problem on my own. (That doesn't mean I wouldn't be grateful for any tips!)

cheers!

Swallowtail

I found the wiring diagram. Here it is if somebody has the same problem.

Is assume the Control Unit is 964.618.212.00 (sitting under the dash?).

Can anyboy tell me what and where the "Additional Control Unit Rear Spoiler" is?

EDIT: Both control units are supposed to be under the right seat.

mojorizing

That additional unit is under the passenger seat near the cruise control module. Cars built in '89 and '90 only have it. part no. 96461814200 I believe.

As you can see, it's essentially in parallel with the control module. It's purpose is to actuate the spoiler if the control fails. Porsche removed that backup function with the '91 cars - they don't have the "additional" unit.

Swallowtail

Indeed, you are right. Here are the schematics for the '91 model.

Also - according to the repair manual - on the '92 model the control module moved from "under seat right" to "inside firewall left/right".

I have no idea what exactly this means but I guess I will find out since my car is a '92.

Jonte

This secondary unit is a bit odd for the 89-90. What happens if that one is simply removed?

mojorizing

@Swallowtail - yes, the control module is in the passenger footwell, you can see it if you stick your head down in front of the pass. seat, and look forward. It's held in a bracket with one screw.

@Jonte - not confirmed, but if the control unit is working, removal of the additional unit has no effect on the spoiler. Originally, I believe that porsche thought that if the spoiler didn't deploy at speed the car would go into orbit, or go back in time, or the engine would overheat or some such. Porsche removed that extra circuitry because it was deemed unnecessary expense.

mojorizing

Given that the console switch works, one thing you can check is the power at the switch for power coming from the control module, pin #11. With the console switch disconnected, and everything else intact, and the ignition switch to "accessory", you should see 5-6vdc on the common wire to the switch at the switch( module pin #11). If not there's something up with the module. If so, there's something up with the wiring from the switch back to the module pins #9 and #10