Hello,

I have a 1995 C2 - Last night the interior light did not come on after I turned off the car and open the door. The aftermarket alarm would not arm, so I locked the car with the key (old fashioned way). This morning I went to the car and hit the aftermarket alarm and it did work. I disarmed and opened the door... and this is when all hell broke loose. The factory alarm went off and there was absolutely nothing I could do to stop it. I ended unplugging the battery before my neighbors kill me.

I've tried locking and unlocking the doors manually, but nothing will stop the alarm from going off. The car will not start - I put the key in, ingnition lights come on, but nothing happens when I turn the key to start the car.

I don't know what else to do - anyone has an idea what's going on and what I can do to get the car driveable again?

Thank you!
Marco

 

I feel so sorry for you. This just happened to me Friday night. In a stroke of unusual luck, I was at the dealer. He printed out the procedure and reprogrammed my remote. It lost it again, but would crank and drive with the alarm sounding, so basically we started disconnecting everything we could to make it drivable. Horn is in the back on the driver's side in front of the tranny. 2 plugs on the back that just pull out. Four fuses for indicator lights, one for interior (incl truck & hood). After all of this it just started working again. No trouble since. Replace the battery in your fob now and then look for the reprogramming procedure (it is a strange and quick sequence).

 

Please confirm you have the IMMOBILIZER, not the standard factory alarm. I'm trying to figure out why you need an aftermarket alarm on top of the factory one. In all probability, one of the various items that the system monitors is experiencing a "failure". It could be so simple as a bad door switch. BTW, why didn't the interior light come on? Is it a bad bulb, switched off, etc.? And what's that got to do with your system? Question: Are you rushing to start the car and not letting the alarm signal light go out at "4 p.m." on the clock? If so, it won't start.

 

Thank you for the help...

The car has an aftermarket alarm, which does not seem to be an issue. The car has the factory alarm - I don't think this car has the immobilizer. I don't have a factory key fob, just the Porsche key and the aftermarket alarm fob.

The light not coming on when I opened the door last night was suspicious since it worked just fine. Actually, it also worked this morning when I opened the door and the alarm went off.

I checked the connection of the door switches and both are fine. I also checked the engine lid and hood connections and did not see any lose wires.

What concerns me the most is that the car will not start while the alarm is going off.

Thank you again for the help!
Marco

 

My intuition tells me that something is grounded or shorted that shouldn't be. Like the aftermarket system is telling the factory alarm to go off. It's gonna take some electronic "sleuthing". Did you install the aftermarket system? Can you remove it to take it out of the equation?

 

The aftermarket alarm has its own siren/horn and this is not causing the trouble (at least it is not the one making all the noise). It is the stock siren/horn that keeps going off as soon as I plug the battery back on.

The car came with the aftermarket alarm when I purchased it and it works fine. I'm going to replace the battery in the fob and disconnect the stock horn for now. I can't t-shoot anything with the battery disconnected and the noise if too much while is connected.

What I don't understand is why the car will not start if my car does not have the immobilizer. Does anyone know the ins and outs of the stock alarm and why it would do something like that? I'm willing to remove the aftermarket alarm and just work with the stock alarm - the only benefit is the keyless entry system.

Thanks again!
Marco

 

I would think that eliminating the aftermarket alarm system from the equation would just simplify trouble-shooting the problem with the stock system. If you disconnect the horn, attach a 12v. light to those leads. That way, you'll know if it's "sounding off" w/o the noise.

 

Thank you! I'm going to give that a try tonight and see if that helps. I'll start hunting down the aftermarket alarm and remove it from the car - not sure how involved is to remove, but I'll see if I can find some resources online...

Marco

 

While you're disconnecting the aftermarket system, look closely for any wires that have poor connections (possible opens), frayed insulation (possible shorts) and anything that could be interfering with the OEM system. Label all the wires you disconnect so you'll know where they go if you decide to re-install. Good Luck!

 

Thank you, again! Very helpful...

Just one quick question - does the stock Porsche alarm (not the immobilizer system) prevent the car from starting when it goes off?

 

Yep! P. 17 in the Owner's Manual. Here's what's monitored:
-Doors-Central Locking System
-Engine & Luggage Compartment Lids
-Glove Compartment
-Radio
-Ignition (car Immobilizing Circuit)
If the LED's don't flash when the car is locked or they change to a double-flash after 10 secs., this indicates that not all of the contacts have been closed.
If an alarm contact is interrupted, the alarm horn will sound for 4 min. At the same time, the interior lights and the hazard warning lights flash. If an alarm is set off, the LED's are switched to a double-flashing signal to let you know the alarm has been set off. When a door lock is unlocked, the alarm system should be de-activated and the LED's go out.
If the Central Locking system is not working, the alarm can be primed by performing three locking actions in rapid succession. The LED's will indicate this by a double-flashing signal.

Hope the above helps.