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Discussion Starter · #1 ·
So I never really noticed that the alarm in my R didn't work. You can lock the car, open the door through an open window and NOTHING happens. No lights flash, etc.

The only indication of any alarm is that the little red LED below the windshield blinks if the doors are locked.

Recently, I flipped up my sunroof on the highway, and then it would not come down. Some research led me to believe it could be the alarm siren, because the wiring for the controls run through the siren and it dies after several years. After 4 days, the sunroof began to respond and I got it down...I didn't play with it anymore and I assumed the siren was the cause.

ANYWAY, I replaced the $178 part, and the alarm still does not work (sunroof works fine, but not sure if I fixed the root cause).

Additional info:

No codes or "Alarm Service Required" messages.
Doors lock normally with fob
Map lights have always worked
When the sunroof died, there was no response to the switch...no noise, etc
Holding the panic button on the switch only makes the horn go off
 

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Discussion Starter · #3 ·
Umm...the battery is there...the car starts...what exactly do you mean?
 

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He means when the battery gets old, systems in this car start shutting themselves off progressively. The alarm, moonroof, etc, are the first things to go. Get the battery checked out. When my battery started going I actually had moonroof stlil working for a while but alarm was intermittent, then not at all, then the moonroof stopped working.
 

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He means when the battery gets old, systems in this car start shutting themselves off progressively. The alarm, moonroof, etc, are the first things to go. Get the battery checked out. When my battery started going I actually had moonroof stlil working for a while but alarm was intermittent, then not at all, then the moonroof stopped working.
+1

When my battery went the alarm went off with a dying sound LOL
 

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Discussion Starter · #6 ·
I think my battery is original; it is a volvo battery. I have had the car for ~1.5 years and nothing else has died, but I guess it is worth taking the batt down to Advance auto and getting it checked out.
 

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Some thoughts:

1 - the siren has a back up battery (this is why it's pricey). If the alarm were to be triggered and the vehicle power cut (i.e. unplugged the vehicle battery), the alarm will continue to sound. This battery fails and causes the "service theft system" message to appear. With enough time, the signal from the siren deteriorates and disrupts the UEM's (upper electronic module) serial network which includes the sunroof module. Which is why the sun roof stops responding when the alarm siren goes bad. It's intermittent at first, but eventually the entire UEM network fails.

2 - the alarm "arms" after 1-2 minutes of all doors being closed and the doors locked. Not right away.

3 - New sirens have to be initialized through VIDA for proper operation. Although I have had cases where this step isn't necessary, I do it every time to prevent any issues.

Hope this helps.
 
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