Originally Posted by volosong

Don't know what year your car is, but on my '89...yes, it does have an alarm. Came as a big surprise to me when I went into the store one day while my wife waited in the car. I locked the doors from the outside with the key, as one would normally do. Well, while I was inside the store, she opened her door and set off the alarm. Boy, was that embarrassing! Couldn't for the life of me figure out how to turn the alarm/horn off. Finally called my mechanic and he walked me through the procedure.

However, pulling the radio out will not set off the alarm. What it will do is disable the radio from future use. There is a four digit numeric code that needs to be entered into the radio whenever the battery is disconnected (like, when the car is in the shop and the mechanic disconnects the negative strap). The radios are basically worthless unless you have the code. But, there are ways around that. I paid a pretty penny for one local stereo shop to insert a new circuit board with a known code.

What car is this radio being pulled out of? I might purchase your old radio from you. Pay you more if you have the code, less if you don't.