Help !! 964 Alarm Will Not Disengage

[Wrecked944]

God darned freaking piece of ***** 964…okay, normally I love this car, but this week my alarm system has decided to misbehave. Basically, the car always thinks the doors are locked. So even if I unlock them (with the key or manually) , the alarm goes off and the car will not start. At first I figured it was caused by the heavy rains - like maybe some water got onto the microswitch in the door. So I left the car alone until today and figured she would be okay when the sun came out and everything dried out. And sure enough, she started fine this morning and drove to work. However, the console light kept indicating that the doors were locked even though they were unlocked. And as I drove to work, the doors kept locking BY THEMSELVES. So obviously she thinks her doors are locked all the time. And then when I got to work, I opened my door and the alarm went off. Grrrr !!! So unless I get lucky, I can't drive the car home tonight. So is there a way to either fix this problem easily in the parking lot under a street light or is there way to disable the alarm so I can baby her home?

[GB83SC]

I would try to disconect the fuse to the alarm and wait a few minutes to see if that works to reset. If that does not work. then I try the battery.

Good luck.

[87turbolook911]

I concur with George, but if you still have problems then follow below:

If it's an aftermarket alarm, you can hunt down the alarm brain and pull the fuse to the power line for it. Typically it's a yellow and/red wire.

You only want to do this if everything is working now. This way you will have effectively disconnected the alarm and any features associated with it (ie remote door locks and starter kill).

The brain is typically hidden somewhere high in the dash. Won't be too hard to find (unless installed by someone really good), just follow the wires that don't look factory.

Then proceed to a good car stereo/alarm dealer for a new alarm

Good luck.

[Wrecked944]

Thanks for the replies. I'm feeling pretty screwed by this simple little problem.

It is actually the factory alarm. I just spent some time hunting around the trunk to see if I could find the brain. No luck yet but I'm sure if I keep trying I'll find it. I understand it is internally fused. So I assume I can just pull the fuse when I find the box. That should get the lights to stop flashing and get the horn to stop beeping I hope. Aaahhh...but I don't know if this will also disengage the immobilizer feature. I wonder if I need to jump the DME relay in order to get the car to start. I sure hope not.

UPDATE: I suspect both door switches are toast because the alarm is only supposed to activate when BOTH doors are locked. I find I can unlock the doors with the key but they won't lock unless I manually crank the door lock knobs (same with the center lock button). So I assume it always thinks it is locked on both doors. Giant PITA.

OH, BUT WAIT !! Maybe since it happens to have impacted both doors simultaneously, I wonder if maybe some water got into the alarm brain itself? I found some dampness in the trunk area when I searched it so maybe she sprung a little leak during the deluge. Hmmm…now I've just got to find that damned alarm brain…

[nestorjw]

Sorry, i had to mention i had a great laugh reading your "how not to rebuild a porsche 915 transmission" very worth the read.

[911C4]

The alarm control unit is located on the passenger side trunk hinge. You need to open the trunk an look where the hinge is attached, the alarm control unit has a blue connector and a separate connector for power, you need to pull the power connector. It would be easier if your dash was out and you will see the control unit better.

[Wrecked944]

Originally posted by nestorjw
Sorry, i had to mention i had a great laugh reading your "how not to rebuild a porsche 915 transmission" very worth the read.

Hey, no need to apologize. That's what it's there for !! I'm glad you liked it. Perhaps I will soon be adding add a section on how not to fix your alarm system !!

911C4 - Thanks!! I am on my way down to the parking lot right now to give it a try. Fingers crossed.

[Eric Coffey]

just a side note:

If it is the same factory system as the late `89 Carreras have (LEDs in the door lock posts), you can compression-start the car if needed.

[Early_S_Man]

Janus,

Surely somebody out there has the 964 service manual and can tell you how to 'officially' disable and bypass the alarm. It sounds like the central locking is causing the problem to me, but it doesn't really matter if the alarm control or central locking caused the problem -- when you can't start the car!!! Good luck!

[Wrecked944]

I just tried pulling the fuse on the door locks because the central locking system certainly appeared to be malfunctioning. But while the electric door locks now no longer work, it didn't stop the alarm. Damn, those Germans were clever when they designed this thing. Funny, the alarm will stop when I turn the key to "unlock" the door. But then when the key comes out, the alarm is enabled again. But while it is turned, I can open doors and do other stuff no problem. If I only had two keys, I could probably put one in the door and use the other to start the car !!

So then I unplugged the alarm box by the gloxe box and now the alarm does not work. However, the car won't start either. Hmmm…I actually got it out of the car and it has a part number of 928.637.104.05 along with a wiring diagram on the face. I think these things can be jumped, right?

Here is what it looks like...




As for manuals, I already own the book by Adrian Streather and it doesn't include info on bypassing the alarm. Neither does the owner's manual. Does anybody have a shop manual for the 964?

[Lorenfb]

The alarm unit does NOT have a fuse inside. The connector must be connected
to the unit for the car to start. The DME relay won't be powered-up without the
connection. Check the wiring diagram to bypass the alarm.

[Eric Coffey]

Originally posted by JanusCole
I think these things can be jumped, right?

I Don't think you can jump-start it. If it won't start from your (good) battery, another isn't going to help. Like I mentioned above though, you should be able to compression-start it, if it's a manual. Just get someone to give you a push, or find a slight downhill grade. Just make sure the key is "on". Good luck!

[Early_S_Man]

Janus,

To bypass the alarm and enable starting ... same drill as for SCs, Carreras, and Turbos.

Fabricate a short jumper, 3"- 5" long, 14 ga or 16 ga wire ... install male 0.25" Faston tabs at both ends. The jumper goes in the connector at the mating locations for terminals '61' and 'A' on the alarm module ... should be blue wires going to those locations.

[Lorenfb]

And how to steal a Porsche! The internet is great isn't it for any info.

[Wrecked944]

Thanks Warren, you are incredibly helpful as always !! I'll give it a whirl and see if I can get her going.

And as for Loren's point, I was actually thinking about the same thing myself. Maybe we can ask Wayne to delete this thread? Seems like useful info if you already *own* a 964. But otherwise, you're right. It is an unintended freebie.

[Early_S_Man]

Well, Janus, you don't have to ask Wayne to delete the thread ... just 'edit' the initial post, and check 'Delete this thread' ... only the thread originator can do that, except for moderators.

BTW, this info first came up in a March 2002 thread ... so it has been around for awhile!

[jtkkz]

Hope this helps, but according to the 964 tech data book that I have:

Alarmsystem/central locking control unit: located under right seat

[Wrecked944]

Good point. My tech says the alarm has two components and one box (with the central locks) is under the driver side seat. But he also says they made a lot of changes after 89. So maybe yours is under the passenger seat? I checked under the seats and the carpets are damp. So I suspect the underlying problem is that water got in during the recent heavy rains. I've got the windows open and the carpets up to help it dry out. But in case that doesn't work., I'm still trying to bypass the alarm. Damn, this alarm is a PITA !!

[Wrecked944]

UPDATE - I got the car running last night and got home. Since it has been an intermittent problem I basically waited until the car would start. Once home I tried using two keys - one to turn the ignition and the other in the door lock. And believe it or not, this WORKS. With one key, the alarm goes nuts and with two keys she works fine. So for the moment, I will pretend the car has an external "kill switch" in the door lock requiring a separate key.

As for bypassing the alarm module, it turns out the 964 has only one blue wire. So I could not figure out where to jump the connectors. There is a blue/brown wire. And I tried jumping to that but had no success. So anyone trying to steal a 964 will get no help from this thread. Indeed, if you need TWO keys to steal the car then you are a very poor thief.

As for the underlying problem, my current theory is that it is located in the central locking system. According to Adrian Streather, the thing has two relays - one for open doors and one for closed. And it has a central module under the dash (or under the right hand seat for later models) which can sometimes fail as well. So I figure I'll start by replacing the relays (once I locate the thing) and the if that doesn't work I'll inspect the main module.

Anyway, thanks yet AGAIN. You guys have saved my butt more times than I can count. This BBS is really quite unbelievable.

[JasonAndreas]

I'll be in Worcester on the weekend and if it would help you I can bring a hammer and a multimeter over to help find the open circuit that is setting off the alarm. Or, I can meet you somewhere between Worcester & Northampton during the week (or you can come here). let me know...