Alarm gone wacky

smooz · smooz's Garage

Here's the situation. I bought the 86 911 Cab back in April. The guy I got it from gave me two keys. The wheel lock and the ignition. I never had a Porsche before and didn't know I needed an alarm key. I read the owner's manual and found that it has an original equipment alarm with the lock in the inside of the door.

Any way, I washed the car tonight and opened the door and the alarm went off. Now the alarm goes off every time i open the door and when i try to start it the alarm goes off and the car won't start.

Never had an issue before. Should I just wait till it dries and hope it works?

BTW - I can't find a new alarm lock or key on Pelican Parts.

Por_sha911 · Por_sha911's Garage

Although it might be OK when it dries out. What happens when you get stuck somewhere in the rain? Replacement lock and 2 keys should be under $100 and can be ordered. Call PP on Monday or you can order it from the dealer.
Edit: did you locate the key cylinder in the door to verify it is a factory alarm?

smooz · smooz's Garage

It dried out and is just fine. I see your comment about getting stuck in the rain. I'm wondering if a new lockset will fix the problem or if I should look to fix something else. What I'm saying is, I'm not sure it was the lockset that got wet and caused the problem. Even if I had the alarm key, I'm not sure I would be able to "disengage" it. The alarm was turned off yesterday before the problem started.

Yes iit is original equipment.

Por_sha911 · Por_sha911's Garage

The rest of the alarm is in the cabin away from water. Only the lock is where water could get to it. I guess that it is the problem. Try to duplicate the failure by running a small amount of water on the lock and see what happens. I know that the alarm looks for a certain resistance created by the lock cylinder. If not found, no start. Maybe you can see if someone has a lock that they removed from a car (like a race car or a roller). It doesn't have to have a key, just be connected and in the disarmed position.

wastintime · 05-19-2007, 10:03 PM

alarms ruin porsches... rip it out of the car

84toy · 05-19-2007, 10:11 PM

What I think of alarms

Por_sha911 · Por_sha911's Garage

I'm sure that our new member smooz is very impressed with what we think about alarm systems but unfortunately that does not answer his question or help him fix his car.

Bump for smooz to see if anyone has an idea of how to diagnose and fix his problem.

DavErb · 05:17 PM

The Bentley manual for the SC's has an alarm section. If the 87's are anything like that then find the alarm unit module tucked away behind some vent hoses in the luggage compartment. Pull the connector block off it and jumper the 2 #61 terminals. That will take the alarm out of the loop and restore order to your car.

Once you've got the car drivable again you can take your time troubleshooting the alarm system. I'd open the door panel and get the alarm lock out so that it can be both: A) dried out completly, cleaned and B) taken to a qualified locksmith who can make you a proper key should you ever desire to use the system again.

Like I said thats Bentley on the SC's ;maybe you should pick up a coopy of Bently on the Carreras

schoward · 05-22-2007, 05:23 PM

I would try the water trick near the lock, but perhaps the below may help as well....

Do a search on my username; posted a fix a while back for a problem that is similar. My door key was losing connection to the alarm module intermittently due to the wires. I dont think my fix will be the same as yours but concept is similar.

In my research to fix my problem, I came across another guy who had same symptoms you describe. I believe his situation was something like this -- He got his car back from body shop and alarm would do same thing as yours. He went in the door to find the shop bumped one of his wires off the connector on the door key switch. Problem fixed.

Based on my problem and that example, I would guess the connection between the alarm brain and the door key is being 'broken' or grounded at some point. I have heard of wires getting chafed in the door jamb etc. also causing this. Perhaps water is causing your issue (?)

I believe the reason goes something like this: Even when turned off, the alarm brain is looking for a certain amount of ohms resistance in the key switch -- kind of telling the alarm that the key switch is there and intact. Breaking the connection and causing 0 ohms to be found makes the alarm brain think that the switch has been tampered with or removed which should cause the alarm to sound. That all sounds pretty high tech and not sure I believe our alarms were that fancy, but only thing I can say is that I've seen and heard of alarms doing very weird things when you interrupt that connection to the key switch. On my 81SC the wires going to the switch were a tan/brown pair I believe.

Anyway, just a possibility....good luck

I got a new switch and 2 keys from Automobile Atlanta. Get the part # and call pelican.

schoward · 05-22-2007, 05:29 PM

My car occasionally honks at me - 81SC alarm

Correction - wires to key sw on my SC are grey/brown. hopefully same as carrera

rusnak · 05-22-2007, 07:05 PM

interesting thread. My first thought was the problem was in the wiring inside the door lock post, not the key switch.

The alarm not only makes noise, but it makes it almost impossible to start the car. Vastly slows down a car thief.

This is a good thing if you're in a high auto theft area. Alarms may not be sexy, but getting your car ripped off is even less sexy.

Also, the alarm key is NLA. I've been waiting for one from Porsche for over 3 months now. I ended up getting a used one.

schoward · 05-22-2007, 08:36 PM

Not to argue - but Automobile Atlanta still has the key switches with keys available on their site -- $98. Not sure how long it will take to get but mine arrived in a about a week or so when I ordered from them in 2005. Brand new genuine porsche part with keys and was a dead on match when I removed the old on from my door. Again, call pelican. Part # below.

Part #91163710100 - alarm switch with keys; 911 1978-89, 924 1980-88, 924 turbo 1980-82, 911 930 turbo 1976-89, 944 1983-88, 944s 1987-88, 944 951 turbo 1986-91 Image Position: 12

smooz · smooz's Garage

Folks,

Thank you for all your input. Special thanks to Por_sha911 for bumping my post and all of you others who helped add input to the solution to my problem. I continue to be imprssed by the vast knowledge of the folks on this BB.

Take care all!