Picked up a '94 850 T-Wagon a few weeks back. Haven't been able to identify the disk shaped object with wire bundle attached shown in photo anywhere in Haynes. So-what is it? Threaded stud in center-looks like something may be missing , also. Thanks

Ah, you beat me to the punch. I was going to ask the same question. My first thought was that it's a horn, but the horns (2 of 'em) are mounted in front of the radiator. My second thought was that it's a seperate horn for a factory security system, but I've never had any kind of security alarm go off on this car or my previous '94 and wouldn't know what to do if it did.

I'm sure someone will enlighten us.

This item is the horn of the vehicle security system that sounds an audible alarm if someone tampers with the vehicle.

It looks like yours has seen better days - there's not much left of it.

Ah, a factory alarm. Never knew I had one.

So, what triggers it? I assume, as was the case with other cars I've owned, if I leave the windows down but lock the car, and someone reaches in and unlocks it without the key the alarm will go off, right? What else will set it off? I've never had mine go off on either 850 I've had. And I assume you shut it off by using the key to unlock the door?

The Guard Alrm 2 late version was the system that had an audible horn fitted.

In this system all the alarm sensors (door locks, bonnet, boot, broken glass, temperature differential etc.) feed into a solid state anti-theft alarm module that plugs into the relay board fitted up under the dashboard (relay 210/211).

Once the alarm is activated by pressing the alarm button on the key fob, the turn signals flash for a short period to indicate the system is activated.

Now, if any of these sensors are triggered, the anti-theft module is triggered and sends a pulse to the horn and turn signals which in response, honk and flash.

That's my understanding of how the system works.

However, as some owners experienced annoying phantom triggering of their vehicles alarm system, to prevent this happening, they disconnected the horn.

Thanks for the education. A project for the far, far future.

Someone might find this helpful its how to reset your key fobs: http://www.quickbrickmotorsports.com/tech_850keyfob.html

It definitely is part of a horn.

Its one of those lame Volvo ideas.

I dont know about that, i kinda like those dish-types, as opposed to the spiral-type.