Lack of the alarm going off seems to be relatively random on the GM sirens. Some do, some do not.
After reading the different threads on replacing the alarm siren, I decided to take action on my Maranello today. I wrote a procedure to perform the operation. It's not complicated and it allows you to spend some time with the car while waiting for the spring outings. Hope this will be helpful. Fred.
Fred- That is great. Saved to hard drive. Just so everyone knows Mark (Gobble on FChat) takes the GM siren and changes the EPROM (or whatever it is) to the Ferrari programming so it works exactly like the OEM siren. On some Ferraris, the actual alarm function on the GM siren does not work, even though it beeps like the real thing when the fob is actuated.
Are you saying that the alarm doesn't work, Taz, or that the siren doesn't sound after the alarm has been triggered? On the F550 and F355, the immobiliser ECU is also wired to the horn relay, so it wouldn't really matter if the siren activated for the actual alarm function. The horn should still beep. A couple of weeks ago, I replaced my F355 siren with an OEM siren (batteries were 7 years old). Although I was able to split the old siren case into two with only one minor scratch and had replacement batteries ready to go in, I decided I didn't want to mess around with glue and such to put the old case back together. The new siren sounds a little different during arming despite it coming from the factory. I wonder if it is actually a generic GM siren. I haven't tested the alarm side of it yet.
Ian, sometimes at least in the 575 the GM alarm does not function completely as the original. It arms correctly chirping and lights flash but upon activation from a door or such being opened, the lights would flash but no siren. It does serve the purpose of killing the dash alarm light though. Its interesting that the alarm only last about 6 or 7 years in the Ferrari. Have owned a 2006 C6Z Corvette since new with the same GM alarm onboard and never had to replace it. In the 575 I’m on my third alarm, last two being GM parts. Taz, curious does Gobble sell the modified GM alarm or just offer the service to modify. Thanks for that info, good to know. Bill FL
Maybe the 575 doesn't have the wiring to the horn? If it does, I can't see how changing a siren would change the behaviour of the horn. On the F355/F550 there is a separate pin on the Immobiliser ECU for the horn. I guess it's up to wiring and immobiliser ECU programming.
Ian- The GM and Ferrari sirens have different programming. Works on some Ferraris, not on others. Bill- I think Mark is just selling them after he modifies them. He says it is not a money-maker and more of a service.
Understood, Taz, but I'm trying to make the point that siren programming shouldn't affect horn relay operation. You don't need the siren to work if your immobiliser ECU triggers the horn. The horn is just as loud as the siren. Image Unavailable, Please Login Have you tried triggering your 575 alarm to see if the horn operates?
Ian- I still have the original Ferrari part in mine. Whether or not it should affect horn operation, it does and neither the horn nor the siren work on some Ferraris with the GM siren.
Thanks, I wasn't sure if the horn was hooked up on your car (normally) Baffling. Maybe the siren program is actually telling the ECU how to behave.
