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Discussion Starter · #1 ·
When my 99 F355B first arrived

When my 99 F355B first arrived I noticed that a red LED in the center of the dash stayed on. I did not care much at first until I drove the car at night and then it was very annoying. The alarm manual was useless to me in finding a solution.

The strange thing was that the alarm worked. If I alarmed the car and reached in through an open window to unlock it, the alarm siren would go off. The remote entry key FOB worked perfectly. So I was stumped as to why the light was on. I decided to go online and search for a solution and found a website called ferrari-talk.com. After several nice chatting sessions with some very great people it was clear that the reason the light was on is because the car ECU senses that the batteries in the alarm/siren are dead or that they are not taking a charge. In searching for a fix, most people said that it would cost $500 for a replacement unit and labor. What? A new alarm with installation at a local shop is only $300 with many more features!

JR of http://ferrari-chat.com mentioned that he heard that the batteries in the alarm unit could be replaced. My car was in the shop for a front bumper fix after a run in with a deer, so I decided to see for myself.

Here is how the problem was resolved.

First, the unit is on top of the left front wheel well. It was easy to see with the front bumper off. The unit is held on by two bolts and a wiring harness:




Here is a top view of the unit once removed from the car:


A razor blade was used to go back and forth along the seam to take the unit apart. I wanted to use a dremel tool to get through it in a few minutes but a friend said I would remove too much plastic and it would not fit right when I tried to glue it together again. Caution must be taken not to break the four legs that hold the circuit board.


Next are pictures of the unit opened:



Once opened it was found that the contacts shown in the picture were corroded. A pencil eraser was used to clean the contacts:



The batteries were also cleaned and a multimeter was used to test the batteries. Both 3.6v batteries were good, putting out 3.8 volts. The part number on the battery is Z3A120 as can be seen in the second photo:



Here is a close up of the writing on the outside of the siren unit:



Next I put the unit back in the car to test all of the functions and everything worked perfectly! Next I disconnected the unit from the wire harness again and glued the unit closed. I only glued the unit in four places to give it enough strength to not come apart and put it in a vise to dry over night:




Before putting the unit back in the car, I ran some black silicone around the seam to seal and weather proof it. It looked to me like moisture may still get in through the siren end, but that is the design so I did not mess with it.

In the process of doing this, I misplaced the 6 inch 4 wire harness that connects to the unit and also connect to the car's wiring harness :-(

I ordered a new one, the price was $60 and the
ferrari part number is: 180072

As soon as the part arrived, I found the old one in my office!


Hope this helps others who have the same problem. To some it may not be worth the hassle of getting to the unit and opening it. I did it because it was easy to get to. The car worked fine with out the unit so I was not all that worried.

I did a Goolge search for the batteries and found many sites that seemed to have it. The sites were all in German. Since I did not need new batteries I did not look into it further.

Feel free to send me email through the web site.

--tony
 
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Discussion Starter · #2 ·
Hello
I have the same led pro


Hello
I have the same led problem on my 99 f355. Can this alarm unit be accessed without the front bumper being removed? Thanks for any help
 
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Discussion Starter · #3 ·
Hi Mike!
Yes, you can access


Hi Mike!
Yes, you can access the alarm without removing the bumper. You need to remove the left front under tray. If I remember correctly, you need to loosen some screws in the wheel well to remove the panel.
Good luck!
--tony
 

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Tony, I have same LED problem on 2000 F360. Has anyone done the fix on a 360 and what info do you have?
mcwrd,

The same fix is possible for the 360! rayjohns on a different forum called ferrari chat . com opened up the 360 module and put an external batter on it so he did not have to worry about the expensive internet battery. I also know you can interchange the 355 and 360 siren module.

Good luck!
--tony
 
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