Factory alarm starting to love my porsche

[janz]

86 Carrera coupe. Now I''ve owned this car for 3 months, got all the electrical gremlins out and replaced a lot of suspension and drive line parts along with new brakes and all kinds of replacements because they were just old and I was afraid of failure. I have over 400 hrs working on it so far, I know to some this would be considered only the beginning. Put over 1,000 miles on it and no problems. PO knew nothing of what was done or needed to be done on the vehicle. I see there is a key lock on the drivers door when you open it and look at the latch part. I look in the owners manual and it says to activate it you turn the key clockwise 90 degrees to activate. PO knew nothing about this but did give me a bunch of keys of which I think the alarm key is one of them. I am affraid to activate it to test it as the car starts and runs great all the time. If I do activate and test if its working what should I expect to happen? Will a horn sound? Will the fuel flow be cut off? what happens if it does and I deactivate it but doesn't work? Will I be stuck with the horn going off and no fuel flow forever? Is there a way to deactivate it if the key fails? Should I or shouldn't I, is it worth having a working origonal alarm on an 86 car? Am I asking for trouble wanting to see if it works? One other ? do the interior courtesy lights have to be in the position so they work when the door is opened for the alarm to work, I usually leave these off because mostly drive during the day (have trouble seeing the dimmly lit guages at night) and have the doors open a lot while working on it in my garage. Maybe I should just not post this thread and leave well enough alone but you all know if your a porsche owner you have to keep exploring the unknown (to me anyways).

[jh225]

I actually went as far as sticking my alarm key in the hole, but chickened out and didn't turn it on. Have no idea if it works and how it works. The manual says to slightly open the door when alarm is set, insert key, and turn off alarm.

What rocket scientist designed that?

[janz]

Mine says the same, makes you wonder. I know I'll do it as soon as I get bored enough once I run out of projects or new parts.

[Chris'85]

I actually tried mine and here's what happened. Put the key in and turn it to activate the alarm, shut the door, did not lock it. Open the door.... nothing, put the key into the ignition and tried to start the car and the alarm horn went off, I did not think about trying to start it, I was in a parking lot at the time, put the key in and turned off the alarm. Horn stopped and car started fine. Anyway that's my two cents.

[wolf]

wouldn't open pandora's box.

[jh225]

I think it is hilarious that we all have a factory alarm that is over 2o years old and we are all equally scared to try it.

[javadog]

You guys are hilarious. The factory alarm is pretty simple and I've never had problems with one in over 20 years of using them.

To arm: close door almost all the way, insert key and turn 90 degrees or so. Remove key before shutting door (some people have screwed this part up and shut the door with the key in the lock, thus braking the key in half and scratching the paint on the car.)

To disarm: Open door slightly, just enough to insert the key. Turn it the other way 90 degrees or so. Note that if you open the door very far, the alarm will go off.

Note that the alarm key is different from the ignition key. They are hard, if not impossible to get without ordering a new lock, so don't lose them.

JR

[scarceller]

Took a very quick look at the schematic for the 84 Carrera and the alarm system is tied to the DME relay. Looks like if the alarm goes off the DME relay will NOT activate and the entire DME gets NO power. Thus you can't start the car.

The DME relay activation comes via the Alarm module, this means that when you turn the key to run or start the DME relay is activated by the Alarm module and is commanded to turn the Relay on but if the alarm was triggered the Alarm Module simply ignores the Run or Start mode of the ignition switch and will not activate (energize) the DME relay.

The alarm module is in the front trunk under the wipers. It's a small black box.

[scarceller]

Here's the schematic from the factory manual:



The Alarm module applies 12V to pin 86 of the DME relay to activate te relay.

[smarjoram]

I have an 81SC and it works just fine - louder than my aftermarket one. Didn't know about the DME - that's good.

[Por_sha911]

Originally Posted by javadog

To arm: close door almost all the way, insert key and turn 90 degrees or so. Remove key before shutting door

Slight correction on above info: You don't have to "close the door almost all the way". The alarm does not arm until 1) the alarm key is turned and 2) the door is closed (regardless of whether you lock the door or not).

Once the door is closed, you do have to open the door just barely enough to get the key into the alarm lock to disarm it. It took me a few tries to get the touch just right so I didn't set off the horn every time I tried to disarm the alarm.

Lastly, the alarm sets off the horn and disables the fuel pump via the DME so it has some value but reality is that if a thief wants the car, they'll get it one way or another. This is why God invented insurance. I use mine on occasion and it works just fine. I'd trust it before I get some hack "custom" installed system.

[Mattcamp]

Mine works fine too. Turn key and close door to arm. Open door and a horn different from the horn on your steering wheel blows. The car won't start until the alarm is disarmed with key. Only problem with mine is that I cant open the door enough to disarm without setting the dang thing off.........adjustment maybe??

[Mysterytrain]

Sal,
By the looks of the circuit it appears that if the system fails that unpluging the box removes the problem and you are on your way once again, but alarmless? Or are there jumpers that are required?

[janz]

I think the opening the door thing is connected to the courtesy light so if you open it to far the light switch activates the interior light and the alarm. Now I wonder if you have the interior lights at the selection that keeps them off if the alarm will sound when the door opens or does it wait for some surge of power like turning the key to on to activate the horn and cutoff? I think I am going to try it out tomorrow after work. Glutton for punishment.

[Joe Bob]

Pandora's box need to be kept closed.....I wouldn't touch it if you paid me. They were pretty cheesy back in the day, age hasn't improved it.....

[janz]

Oh come on Mikez where's your sense of adventure? Isn't that why we own a porsche? Besides I always liked the name Pandora. Let you know tomorrow how it goes.

[Joe Bob]

I spent hours tearing out the remnants of the stock and aftermarket alarm. It was a nightmare. Really screwed up my electrical system when it shorted out.

Be weeeerrry carefuwlll.....

[Dai]

I have been wanting to asked this question but was leery of asking. I'm glad someone have asked. Too funny.

[Chris'85]

Interesting... I need to replace my door light switches, because they don't work, so when I open my door the alarm does not go off. It was only when I tried to start the car that the alarm sounded.

[scarceller]

Originally Posted by Mysterytrain

Sal,
By the looks of the circuit it appears that if the system fails that unpluging the box removes the problem and you are on your way once again, but alarmless? Or are there jumpers that are required?

Ron, I think that if you unplug the box the DME relay will never activate. That black wire that feeds pin 86 of the DME relay would be left disconnected. I think you would need to jumper this wire to the run/start line on the alarm module. Just a guess.