Ok so we are all sleeping tonite and I am awaken by a car alarm. Not thinking it was one of ours.

Well it was. My mom's 2000 s80 2.9, it went off once then again before I could get to her keys and unlock and relock the car.

I went outside and checked her car no signs of human tampering.

So I lock it come inside lock the house and try to go back to bed. 5-10 minutes later same thing happens.

Again no signs of tampering, this time I got mom and day up for it.

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So what could be the culprit? Fuse, faulty wire, a wire somewhere shorting the system, battery, etc?

 

Turns out it was a faulty siren.

Which doesn't make sense, since we could hear it going off. So the siren works.

So the real answer is that, the system thought someone was trying to disconnect it and it was going off because of that.

CASE CLOSED

 

open shut case lol

 

The siren is like a little computer. When it goes bad is shorts out and goes off.

 

I have an alarm issue too. 1999 S80 T6. Sometimes when i use the key to open /unlock door, alarm is triggered. Weird thing is that when door is opened, alarm siren goes off at almost a whisper. Why is my alarm going off anyways. Whys is my alarm like a whisper joke? Thanks

 

Bad SIREN

 

i have the exact same problem with the alarm going off continiously but my siren has never worked so I guess my siren is bad (hazards just flash). Anyone know where its located and the part number so I can pick up a new one?

 

It is located in the R/F fender.
Call the Dealer for the Part Number because I believe there is a couple of different ones. They will need the last 6 of the Vin to look up the right one.

 

called the dealer and the part is $200! I want to just disconnect the siren but I am wondering if this will still give me the same problem of the alarm going off continiously minus the siren? It may just have come loose as I have a loud rattling sound in the right front fender when going over speed bumps. Whats the best way to access the siren? Thanks
Andrew

 

You have to drop the inner fender liner.
But you may cause more problems unplugging it.
It is basically a computer.

The noise I will bet is either a bad strut cap or sway bar link.

 

I will try 2 get in to the siren today and let you know. Thanks for the help Tech.

 

No problem anytime.

 

I have a 99 S80 2.9 and recently the alarm started going off for no reason. When the alarm is triggered the keyless entry remote does not work, the alarm sounds for about 2-3 minutes stops for about 10-20 seconds and then repeats this cycle. Since remote does not do anything at this point I have to use the key to open the trunk and remove the negative battery cable. Sometimes I can return the cable immediately and the alarm turns off and the remote works again, however sometimes I have to leave the cable off for up to an hour. Right about the same time the alarm started acting up "SRS Airbag Service Urgent" popped up in the messages. TECH you seem to have all the answers here I hope you can help. Thanks

 

Alarm siren is bad.
That will mess with the computers.

 

This is a great site. You guys are great. Thanks to your expertise, I have solved many problems without paying the high dollars to the dealers. I need to know how to enable/disconnect the alarm on a 2000 Volvo S80

 

If you have the right part, can this be done at home or does it require software update? (replacing the siren that is) - why the hell couldn't they just use the damn horn like every other frickin car company - starting to really HATE VOLVOS!!!

You'd think there'd be a recall on this as there are so many people that seem to have this issue.

 

You can replace it no software needed.