Prof Requiem

Greetings all,

I have an '81 928 Auto that I bought May of last year and have been doing various restoration projects on. Most recently I discovered, thanks to a Rennlist forum thread, that my CE Fuse panel was from the wrong year so I replaced it with the proper one. Generally this has improved things, but I had a weird issue develop lately. I had accidentally left my keys in the ignition overnight which drained the battery to nil so I hooked up my trickle charger and charged up the battery. Then when I unhooked the charger and opened the door, the car alarm went off.

Now, up to that moment I did not even know it had an alarm and it had never gone off before under any conditions. I wasn't sure how to turn it off since there is no wireless clicker since it is such an old car (and I was admittedly surprised it even had an alarm in it) but when I tried the key the alarm turned off but the car won't start now. Whenever I open the door the alarm goes off and I have no idea how to disarm it beyond engaging the key in the ignition (though again it won't start). I tried turning the key in the door but the door lock is somehow disabled and the key just spins and spins but nothing happens and it doesn't do anything to the alarm. I have searched the issue on the forums but wasn't quite sure what to do in my specific situation. On my 944 the alarm has a second key hole next to the driver's door but this car doesn't seem to have anything similar. I am not against disabling the alarm entirely but would rather just turn it off if that is possible. It is a very weird situation and it appears that the alarm is disabling the fuel pump so until I get it resolved the car is stuck.

Any help is greatly appreciated!

Wisconsin Joe

You should have alarm switches in all 3 lock cylinders (hatch and both doors).

The alarm is armed by turning the key to "lock" (or left in the hatch). It's disarmed by unlocking the doors or opening the hatch with the key (using the inside release won't do it).

The alarm also includes a "start disable" (both fuel pump and ignition IIRC), so you are right that it won't start until you shut the alarm off.

This is a thread about the hatch lock that I found very helpful and informative:

https://rennlist.com/forums/928-foru...larm-lock.html

Or you can simply bypass the alarm (you'll have to search that one out yourself).

And don't feel too foolish that you didn't know it had an alarm until it went off.

I had the same thing happen. I must have jumped a foot or two in the air when it went off the first time.
My hatch lock didn't work right (that's why I have that thread handy) and I had armed it by turning the key to the left. It went off when I opened the driver's door.

joejoe

Is the key you are using the one for alarm, or the shorter key? short key will not disarm.

Prof Requiem

I have both keys, a red and black one, the red one works in the ignition but not the locks and vice-a-versa. I will try messing around with the black key in the locks and see if I can disarm it. Neither of the door locks appear to work (which isn't an issue for me as I live in a very safe area and don't worry about locking my car doors) and the hatch has the issue where it can be closed but it doesn't latch all the way and therefore you can just pull it open without the key. I will try using the key in the various locks and see if I can get it disarmed. Thanks!

Wisconsin Joe

Duh-huh on my part.

I completely forgot to mention that part.

Thanks.

jheis

Post number 2 in this thread:

https://rennlist.com/forums/928-foru...-bypassed.html

will tell you how to bypass the alarm system

James

Prof Requiem

So upon closer inspection my black second key is not the factory original and is some sort of aftermarket key and the same length as the red one. It appears that the black one fits the door and hatch locks and the red one fits the ignition (don't ask me why), but because it is not longer I am fairly certain it will not disengage the alarm. I haven't messed with it yet because of inclement weather of late but hope to get into it this week sometime and see if I can get the system disengaged and if not then I will bypass it via the jumper fix on the z plug on the board. Thanks for the replies everyone I will update once I have gotten it fixed.

oldfrat

I thought the alarm on my '81 was disabled. Then one day I locked it from the passenger side and was amazed to have the alarm go off and the car disabled when I later unlocked it from the driver's side. I managed to solve things by going back to the passenger side and unlocking there --with the same key. If there's a chance you repeated this, you might try unlocking from the other door to see if it shuts off the alarm.

If you decide to get a long key from a dealer via the VIN, be sure to research the threads on this. It was a very frustrating process for me.

Brad

Barry Chan

Just bypass it....unless your car parks in a bad neighborhood all the time?

Prof Requiem

So even though I don't have the extra long key I unlocked the car on the passenger side and that seems to have turned off the alarm as I was able to drive it after that. I am going to leave it as is for now so that I can use the alarm if needed, but if it gives me another problem I will definitely disable it. Even though I live in a very safe area and don't bother locking my car doors when at home (I live in the woods so no foot traffic hence not much chance for random breakins) it is nice to know that I can activate the alarm if I take it out shopping or the like. Still I don't worry about it generally but as long as it isn't giving me a problem I figure I will leave it as is. It is good to know that I can rather easily bypass the system if it gives me any more trouble. Thanks for the replies folks.

oldfrat

Amazing! This 928 newbie and mechanical know-nothing actually suggested a solution that works.

We now have matching 1981 alarm systems. Like you, I kind of like knowing I can activate the alarm system on the passenger side for those rare occasions when I might need it.

Brad

Wisconsin Joe

The alarm switch is part of the lock cylinder. If your driver's door won't arm (or disarm) it, it's a pretty simple task (after the door panel is off) to pull the lock & see what's up.

If you are having the door panel pulled for any reason, have Sean take a look at it.

The Forgotten On

My 81 is the same, it only activates on the passenger's side. But it does work well and I always carry the long black key just in case the alarm comes back to life on its own.

If anyone still has their long key, make a copy of it ASAP as if you lose it, it will cost you months of pain through the dealership.