Security beep

[pbinhk]

I have just replaced the CDR22 stereo with an Alpine head unit (fully ipod compatible) and on locking the car I get the security beep. Is this because the system recognises that the original Porsche/Becker head unit is missing?

 

[Richard_Hamilton]

Yes. The brown/blue wire (which goes to the alarm control unit) needs insulating. If it is earthed, you will get the beep.

 

[Mark_Bennett]

If you look at the original Becker/Porsche unit, there is a patch of insulation on the one of the faces of the casing (I'm not sure, but I'm guessing the top).
This is for the alarm contact (as Richard indicates above). You can put a piece of insulating tape in the same area on the new unit and you will then retain this security feature (the arlam goes off if someone tries to remove the radio (steal the radio!)

 

[Tool Pants]

The original 22 radio has a small insulator on the side for the alarm contact. Aftermarket radios do not have this. You can even see the dent in the insulator in the picture where the alarm contact presses against the insulator. So with the original radio if someone tried to pull the radio out the alarm contact would touch the metal body of the radio and the alarm would go off.

With your aftermarket radio the alarm contact is touching the metal body of the radio all the time. So when you set the alarm you get a single beep to tell you something is wrong. The alarm system works, just not for the radio.

I tell local owners who have aftermarket radios that they might like the beep, as you can hear that the alarm has been turned on.

Otherwise you put a small piece of tape on the side of your new radio to mimic the insulator. Or you disconnect the wire to the alarm contact.

 

[Richard_Hamilton]

I agree with what has been said here, but it always seems to me to a bit pointless having a radio contact. Someone would have to break into the car to get to the radio, which should set the alarm off way before they ripped it out the dash. I suppose that if you locked the car with the roof down it might be useful, but I can't imagine many people expecting their car to be intact if they leave it like that. Also, most petty thieves know that original fitment radios are coded, and usually go for aftermarket ones (which aren't) anyway. (Or maybe that's what all the radio code requests are on Renntech [] []).