mbintx

I've read all of the recent posts on spoiler issues and I'm still not clear on what the actual fixes are. So forgive any redundancy.

My particular issue: 1989 C4. Spoiler deploys at 45 mph as intended, but then will not retract. Only way to retract it is by using the toggle switch on the underside of the spoiler (no internal switch on an '89). When I use the toggle switch, spoiler retracts and extends evenly and cleanly--no sticking or grinding.

I'm reading that this is most likely a relay or spoiler module issue, but I'm still unclear on which is the issue. I'm attaching pics of the two relays situated under the passenger seat. I understand there is a third module/relay somewhere under the dash as well. These parts are not cheap and difficult to find, and I don't want to replace all three if I don't have to.

Has anyone had the same symptoms as me and found the definitive fix for this?

ToreB

What toggle switch are you using and how?
There are two end switches on the spoiler mechanism. One for fully up and one for fully down.
The 96461814200 electronic unit was added for extra safety in the spoiler system to supervise the normal spoiler unit. As far as I know is this not needed for normal operation.

The third unit you mention is probably the speed signal relay, providing the correct vehicle speed signal format for several on-board units. Do you have a On-Board Computer in the tachometer? If this show the correct speed, the speed signal is fine. Your spoiler unit obviously has the speed signal input since it is deploying the spoiler correctly, and it is probably nothing wrong with this signal.

The spoiler control modules have some known internal weak points, and this might be the cause for your problems. This can easily be repaired.
Cheers,
Tore

bw-porsche

The grey control module box, part number 911.618.112.00 is most probably where the trouble is. You need to get it checked either by an electronics engineer, and it would be easy for them to check out, or send it to somewhere like ecudoctors.com who will test and repair for 175 dollars.

Earlydays

+ 1......my spoiler would work erratically and the solution was to replace this control unit. When I replaced mine a new one cost $180!

Lorenfb

My post from another thread:

The control module is very simple to troubleshoot:
1. Once the module is located, carefully slide-out the circuit board while still connected.
The ignition switch should be off.
2. Place the circuit board on something to isolate it (a rag) from having the underside
of the circuit board touch any metal.
3. Once you can view the circuit board, you'll notice two relays. One is the up
and the other is the down.
4. Turn the ignition on and operate the up switch. The relay that closes is the up relay.
That relay provides 12V to the spoiler motor. The other relay which does operate
provides the ground for the motor.
5. Next use the down switch and the relays should reverse, i.e. one closed and the
other open.
6. The motor should then be checked for the 12V and ground.
7. If either relay fails to operate, then;
a. the switch wiring could be bad,
b. the circuitry that operates that relay is bad,
c. the spoiler wiring is bad/intermittent.
8. Either relay can be operated manually (just push contacts closed) to bypass the
circuit board electronics, the up/down switch, and/or its wiring.
9. If the manual operation functions, but not the automatic mode then;
a. the speed signal is bad (ABS speed converter relay),
b. the speed signal circuitry in the module is bad,
c. either limit switch could be bad on the spoiler.

Pdyson4

Hi all, my 993 spoiler raises but will not retract. The motor, console switch and cover micro switches are all good. I’ve replaced both driving transistors and relays for up and down but my down still doesn’t work. I’ve buzzed everything out that I can but can’t find the fault. Has anyone one here had a down failure not linked to the relays a driving transistors?

willmip

I’m going to join this party too, as mine works correctly 90% of the time, but my dash light does not illuminate when I put the ignition on (ever). The bulb works as I’ve checked.

Does the spoiler control module manage the dash light?

Pdyson4

Yes, it's controlled by a transistor. Scroll back and you'll find your answers...

CL5AU

Hi Loren,

Thanks for your post. I bought a 964 a few weeks ago. The spoiler is not raising at high speed nor when using the console switch.
I did what you mentioned, and the spoiler raises and retracts when operating those two relays in the gray Sachs control box. What should I do next to diagnose the problem?

Thanks so much in advance,

Lorenfb

The unit needs to be repaired.

CL5AU

Thanks for replying so fast. There was a small amount of corrosion in the connector pins in the control unit. I cleaned those, and it is working fine!!! So happy.