bmxracer4

I have looked this up in the owners manual and searched this topic and can't find the answer to my question.

I had a stereo installed the other day and when I lock the car the alarm leds on the door start to double blink. Does this mean the immobilizer is in a priming mode? How do I get the alarm back to one blink? Does the double blink still set the alarm?

Thanks for any suggestions, Paul

David in LA

I believe the double blink indicates that either the alarm had been triggered or that the alarm is malfunctioning.

Did you have a new head-unit put in? If so, what did the installer do with the ground wire on the factory head unit which triggers the alarm? (FYI for clarification, do a search on this topic for details on what I am referring to)

Rezal

I have a secondary aftermarket alarm in mine. When I activate that (a double chirp vs. the usual single), I also get double flashing LEDs (vs single).

bmxracer4

David,

Thanks for your post. I did a search on the topics you said and still didn't find what I am looking for. What were the search words in order?

They installed a JVC deck. The installer said he has completed more than a few Porsche installs. I will take it back to them and ask about the ground wire. I have looked at the wiring diagram on the factory radio and don't see a special ground wire for the alarm.

Thanks again.

David in LA

IIRC what happens is that if the radio is removed, a circuit is completed and that triggers the alarm. The ground wire may be attached to the frame that the OEM radio slides into...that was probably removed when your JVC was installed. If I am not mistaken, for the alarm to function properly with an aftermarket radio the wire has to be left off (this also means removal of your stereo does not trigger the alarm). I don't have personal experience on this (still running stock stereo but hope to install a trafficpro) but a few rennlisters had alarm issues when they installed aftermarket radios. If you can't find the relevant thread via a search, you may want to make a new post and link to this thread, or perhaps change the title of this thread so that those who've had the same issue can respond.

Sorry I can't help you more with specifics.

Bijan

I had the same issue, with the Porsche Block System. Turned out the standard radio was not reinstalled properly after replacement under warranty. It indicates minor security issues, I think trunk, possibly glove box lid and radio sensor warning

bmxracer4

David, Bijan,

Thanks for your responses. It was the radio chasis ground not being isolated. The install tech connected it to ground, hence the alarm issue.

Thanks again everyone,

Paul

1997 993 29k miles
2004 Mastercraft X7

Texas993

Any idea what wire it was that needed to be ground properly? Color? My car has an aftermarket stereo and the light flashes twice too.

Thanks in advance.

grmnxtc

Patrick,

Should be a single green wire, normally connected to the frame "mount" for the radio.

It needs to be isolated and NOT connected to ground for the alarm to set properly. If it's grounded, the alarm will prime, but the double blink is telling you that there is a problem in the system (it thinks the radio has been stolen!).

Clive.

STLPCA

Excerpt from my post a few years ago:

The alarm wire itself is a thin gauge solid green wire that comes from a harness well above & to the right of the radio. It is neither visible nor accessible from under the dash - the radio must be removed (makes sense for security - ahhhh German engineering). The alarm connection for the radio is a normally open connection & is triggered when it is grounded. That's your problem, as explained below.

The alarm wire connects to an insulated tab assembly on the radio "cage"/frame/mount (see pic below) that fits in the dash & into which the radio slides. The tab is simply, but ingeniously constructed so that the alarm wire cage tab will be grounded to the radio chassis & the alarm instantly triggered,IF the radio is pulled (as in an attempt at removal).

The problem is that a casual look suggests that the alarm wire is grounded to the cage & is a normally grounded connection - it is not. An uninformed aftermarket radio installer would intuitively reinstall the green wire by grounding it to the new radio chassis. The result is a tripped condition which would allow the alarm to otherwise function, but cause the error LED lights you have experienced. As a test, I grounded the green alarm wire, set my alarm & experienced your described condition.

The fix is to simply disconnect the green alarm wire from its ground connection. However, your radio will not be protected by the alarm. I've thought of an easy, inexpensive way to add back the radio alarm protection. Email me at ibinmo@aol.com if you're interested, but I'm out of town so don't expect a quick response.

Crimson Nape Racing

the lights will double blink if the alarm thinks anything is open - doors, hood, trunk, or even the glovebox. Also, mine was double blinking after I disconected the cheesy Japanese horn under the car. I reconnected the horn to get the "normal" blink back.

Tim993

I have always had the double blinking on my car and never new that it indicated that there was a problem. I bought the car with an aftermarket stereo so I guess that is what happened. My drive block seems to work fine and I just assumed that there was not an additional audible "break in" alarm or that I just had never triggered it. It doesn't seem like there is a problem leaving it this way if you do not mind not having an audible alarm. Am I missing anything?

grmnxtc

The alarm is actually quite "clever" from what i can determine.

There are a number of inputs to the alarm itself. These include the stereo mount frame, the doors, the luggage compartment, the engine compartment, the rear package tray (if you have a rear seat delete) and also some "spare" inputs (at least the wiring diagram implies this).

When Arming the alarm, it looks at the seperate inputs and determines if any of the sensed lines are active (i.e. something is grounded). If so, it still activates the alarm, but notifies you that "something is not quite right" by double blinking the LED's.

To trip the alarm, one of the inputs must go active, i.e. stereo removed, hood opened, door opened etc. However, I don't think that the line that was *already* active would trip the alarm. I.e. if the glovebox was open, then while armed was shut then opened again while still armed, that it would trip the alarm. I think that the system "knows" that that circuit should be ignored, as the "arm condition" for that input was invalid to begin with (and told you so with the double flash).

Some conjecture in the above, but basically the double flash is telling you that one of the input lines is active upon arming. Probably in almost all cases where a stereo has been replaced, that will be the root cause.

Clive.

David in LA

If you leave it as is, you will never know if the alarm was activated in your absence

bmxracer4

One thing to keep in mind is that if you ever need to reprogram your remotes, the double blink could be a problem (it is hard enough without having a primed alarm). I would also wonder about the emergency entry procedure if your key fob isn't working properly. The alarm might think there is a still a minor problem. JMHO, Paul