Siren Replacement

[Voldog]

Hello all. I think my siren needs to be replaced (or disabled). My sunroof started not working, After reading up I checked Fuse #38 wich controls the siren. It is blown. I replaced it and it blew again. After reading forums and Youtube, it looks like these sirens go bad when the batteries inside leak and fry the board. At least I'm hoping thats the issue.

Before buying a new one I was wondering if anyone has a spare they kept after replacing theirs that I can have. I might tinker with it replace the battery.

https://www.youtube.com/watch?v=vm_qGUegzw8

https://www.youtube.com/watch?v=qbaT6fAS6pM

Thanks.

[NTXC]

I just replaced mine which unfortunately had leaked so I tossed it. That said, I replaced mine with one from Eerie VoVo (check out their EBay store), replaced that used battery with a new one.

I spent only $45 on the siren itself.

[Voldog]

I just replaced mine which unfortunately had leaked so I tossed it. That said, I replaced mine with one from Eerie VoVo (check out their EBay store), replaced that used battery with a new one.

I spent only $45 on the siren itself.

I spoke with them the other day. They want $90 for the siren. Maybe its cheaper in their ebay store? There's also an eBay seller (laautoparts) that sells rebuilt units. Battery replaced for $139.

I just don't want the hassle of replacing the siren again.

[Willy]

You can disconnect the siren module. If that solves the problem of the sunroof,
you know that the siren module is indeed the cause of the problem.
You don't have to replace the siren module, there will still be some or or all of the
burglar alarm active, the horn of the car will sound instead of the siren.
Should you leave it disconnected, pay careful attention to keep the conector
away from moisture in order not to blow a fuse or compromise the Can-bus.

[Voldog]

You can disconnect the siren module. If that solves the problem of the sunroof,
you know that the siren module is indeed the cause of the problem.
You don't have to replace the siren module, there will still be some or or all of the
burglar alarm active, the horn of the car will sound instead of the siren.
Should you leave it disconnected, pay careful attention to keep the conector
away from moisture in order not to blow a fuse or compromise the Can-bus.

Thanks. Where Is the siren module located? When you say module you mean the siren unit? Are you saying that disconnecting or unplugging the unit should make the sunroof work again?

And not quite sure what you are saying that there will still be a burglar alarm active with the horn sounding instead.

[Willy]

The siren module is not just a loud horn, it is a CAN-bus member and as such contains electronics.
Some suffer from leaking batteries, mine had water damage. The module is located in the right
front wheel well, behind the liner. It is fixed with a tamper-proof bolt, but this bolt can be removed
by making flat sides to it (eg with a Dremel tool) so it can be gripped. You can use a normal bolt
if you replace the module. Disconnecting the siren module could make the sunroof work again, it
may depend on the specific cause of the problem.
As I found out while the siren module in our XC70 was removed, the horn of the car takes over
(at least for a number of alarm causes) the function of the siren if it isn't present.
There is a lot of info about the siren module on this forum. If you do a search for "siren module"
you will get a long list of hits. After reading them you will be quite knowledgeable about this topic.

[Voldog]

Thanks again. Good to know that it appears the horn takes over. Which begs the question why didn't Volvo just resort to using the horn for the alarm instead of introducing another contraption.

I am looking at three ways to go about this. One, remove and open the module and see if the board is ok. If ok replace battery. Two, get the $138 eBay unit whose battery supposedly has been replaced. Three, get a used module from Erie Volvo for $90. Four, buy a new one for $253 from FCP.

[AKAMick]

When i removed my alarm module to replace the internal battery the horn did not take over the function of the alarm, maybe my car is faulty?.

[Willy]

If I remember well, the horn only sounded for a number of alarm situations, but I can't remember which. I do know I did some tests, possibly the horn sounded when I put my arm in through the open window and tripped the interior motion sensor. But I can't be sure about this, it's a very long time ago. Perhaps Volvo decided on the siren module since it is a stand alone unit with its own battery.

[AKAMick]

Interior motion sensor?, both my XC's do not have that option as i can set the alarm while inside and nothing happens if i move around, only if i open a door it triggers.