horst

I have posted about this before- no one seemed to have a clue. I certainly do not. Why would the tail rise by itself during the night, Key off and /or removed, everything off. Sometimes it will remain retracted for days on end, then as if it had a mind of it's own, one morning I will walk by, and the tail is UP! About the only thing I can think of is there is some sort of current leak that is getting to the mechanism. But how? you can't even manually switch the tail up or down unless the key is on. The only other thing I can think of is that the battery is getting a bit long in the tooth. What is going on???

garrett376

How often does it go up by itself? Weekly? That is funny that it still does this!

I'd try to unplug the control module (what year is your car?) and see if it ever happens again - if it's a weekly occurrence, you should find out sooner than later if that fixes it. You'll be without a spoiler during that time, but I'd bet you've got a bad control module.

Eric Kessel

I had the same problem about a year ago..... over the course of 3 weeks, it would go up by itself
4 times...... sometimes during the night, sometimes during the afternoon....... and then it stopped. I didn't change the battery, or control module.....

-Eric
90 C2
NER/PCA

horst

It's a 90 C4. Frequency? - no rhyme or reason. Sometimes stays put for a week or more, sometimes raises several times per week. Where does the control module live? If I disconnect, would the manual switch still be able to raise/lower? If that is so, and the problem ceases, I could switch my module with friend with a 92 C2, to see if I can transplant the problem.

jimq

Maybe a female 964 is driving by at nite

Arjan B.

Power on the control unit has to stop if the key is out. If the power stays on [please measure by connecting a LED control light over the night on the power input +15] then could be the control unit inside has a short cut or a influence from outside [bad radio connection] is the cause. I think the control unit itself is the problem, a relay does stick inside the control unit.

bhensarl

The control unit is underneath the passenger seat and is labelled, "Heckspoiler", I believe (but don't quote me on that. It's just a little box looking thing with a plug. If you've got Adrian's book, there's a picture of it on page 301. It's the little silver box labeled, "A". If you don't have Adrian's book, go get it.
Brian

horst

Thanks for the input. I will fiddle with checking for current at the power input, with the key out. Should be 0 correct?. Also, I have installed (last year) a Becker radio, with a custom made harness to connect with the Porsche wiring harness, so I don't have to cut anything. If I get voltage at the contol box, with key out, I'll switch back to the Blaujunk Reno. Does that sound like a reasonable approach?

k00k

I've got absolutely no idea, as I dont even have my own 964 yet. But I'll have a guess. Is the mechanism to raise the spoiler done by means of a gas strut? Is the pressure in that magically increasing overnight? Or is it some sort of electrically powered arm?

cheers
Mal

horst

No. Electrical.

Wachuko

Must be having some sweet dreams... LOL