I bought a 2008 C70 in April 2016 with 51 k on it. Then, I have experienced the Volvo alarm siren module within my first 2 weeks of ownership. The VIDA did not show any messages however, the emergency light kept flashing and it came on when I was driving also. At that time I searched around and found many information about how to replace the battery inside the unit. The dealer charged $85 to scan the car and wanted $560 (-$85) if I decided to change the siren module with them. I went to the dealer and was hoping that they would charge about $300 for the part and labor. The siren module was just under the firewall on the passenger side and it eventually took me only 15 minutes to replace. Here are all the approaches that I did.
1) Replace the battery in side the old unit with a dog collar invisible fence battery with the same voltage. It did not work. I went back to the battery store and they said that the battery seemed to be broken and they did not have a new one available.
2) I removed the siren module out from the car and did not drive it for three days. The car would not start and gave me all types of error messages on the dashboard (one of them is the faulty ABS module). Well I was so panic at that point. I disconnected the battery so I would not have to see those messages again.
3) The new siren module that I had ordered finally arrived about a week after I disconnected the battery. The new unit shell was made from metal instead of black plastic. I checked online and the new one is a replacement part of the discontinued part. I checked my car battery and it had about 11.96 volts in it. I decided to get a new battery (AutoCraft Platinum AGM Battery, Group Size H7, 850 CCA) and then installed a brand new siren module that I bought online from a Volvo dealer in Georgia. I introduced the new alarm module by pressing lock on unlock several times. I did both on the remote and on the door panel just to be sure. All the faulty messages went away (did not show up at all). I went to an auto part store and let them checked my charging system and all parts were working fine. I had been driving my C70 happily from the beginning of June until yesterday.
4) When I got back home, I saw that my C70 was flashing (oh noooooooo not againnnnnnn). We had rain and lightening yesterday so I would blame it on those instead of the alarm system. However, the flashing did not stop after I press unlock button on the remote. I manually turn of the emergency light after I got into the car. I could have tried to start the car first before I turned off the flashing light but I forgot to do so. I did not lock the car and the car has not been flashing until this morning. I checked the battery and it was at 12.51 volts (was at 12.91 volts 3 months ago when it was new).
Should I be worried about the alarm siren module or battery at this point?
The fact that the emergency flashing lights did not get turn off after I pressed unlock button makes me worried the most.
Any comments or share experiences would be greatly appreciated.
GoGT