I just bought a 960 with a genuine Volvo alarm that has been retrofitted, it has a glass break sensor that plugs into a very similar harness coming out of the relay, the plug on the relay looks the same but the short adapter is different. My guess is the relays are all the same, but different adapter harnesses plug in depending on what accessories are added to the alarm. I don't know what that harness is for but it will probably be some sort of additional security option,