Problem with my alarm
 

Hey guys. So when i first got my car everyone once in a while the alarm would go off for no apparent reason. It stopped doing that after a while and recently started up again. The last 3 tI'mes Ive unlocked it the alarm goes off. Once in a while when I'm unlocking it, it will force the key to move back to the neutral position and if i open it, the alarm will go off and i wont be able to start the car until it decides to let me. So any idea what the problem could be? If you need any more info let me know.. Thanks SmileWavy

Factory alarm or aftermarket alarm you don't know about thats buried in you wiring?

Factory alarm uses a slightly longer key. Does your alarm behave the same way when you unlock from the other door?

Hmm.. Not sure how it does from the other door, because it doesn't do it all the time. The key is just under 2.25 inches and old as heck so does that sounds like factory?

I had to drIve to meet someone for coffee and then have lunch with my sister, so while i was gone i unlocked it from the passenger side. the alarm never went off. So it seems like the passenger side works OK. I don't think Ive ever had it go off when unlocking it from that side.

This may help with key recognition:
http://forums.pelicanparts.com/uploa...1320445456.jpg

Thanks, yeah that's what my key looks like

Going by the metal that sticks out from the plastic head;

Alarm key is 55mm
Reg key is 43mm

Yeah my alarm key is 55mm

(bump) SmileWavy

So the last few days its been going off EVERY time. Unless I open it from passenger side. Its fine from that side..

You may need to go into the door and replace a switch or ?

Anyway, read this link as a warmup to how the alarm system works.
http://forums.pelicanparts.com/porsche-928-technical-forum/345330-adding-remote-keyless-alarm-ob-1983-a.html

There are two keys for the alarm cars: The black key which is long, or the valet key which is short.

-What is happening is that one of your door lock cylinders has a failed connection, most likely the drivers side. AND, your door lock servos are out of sequence. You probably need to replace the lock cylinder; I think 928 International has these. They aren't hard to change, but they DO require the door panel to be removed. That isn't that big of a deal, but there are a few tricks. You need an alarm-car cylinder; The switch that has failed is mounted on the end of the lock cylinder with a couple of tiny screws. You have to replace the whole thing, which means that the new part needs to be keyed to your car.

This site will help you: Porsche 928 Maintenance Tips and Procedures

In the mean time if you have the red key, just use it. It is short, so it WON'T activate the alarm switch at the end. There IS a way of disabling this alarm system- Once it is disarmed, you pull the connectors in the wires that lead out of the lock cylinders, and it cannot arm.

As to the key being forced back over...the door locks use "servos", or tiny motor devices with gears and an arm, and they have a data link between them. If the drivers door lock cylinder finds itself out of sequence with the other side, it will attempt to move back, and force your key back against your hand. This is because the "pot" or the internal rheostat that tells the servo how far it has moved has failed or become dirty. In the mean time, it has moved the switch at the end of the cylinder, and [Can you tell by now that I've had these problems myself-?] set the alarm. As soon as the door opens, your horn sounds.

Good luck!

N!

PS: If you are smart, you'll just disable BOTH systems and be done with it; If you suffer from low blood pressure, trying to solve these two will certainly solve that problem in a hurry-!

Haha sweet thanks guys. Ill try to get that fixed this week :)