A couple years ago, the alarm in my '96 850 (now 175k) started chirping and blinking without any apparent reason. Being 75 miles from home on a sunny fall afternoon, we drew a lot of unnecessary attention on the PA Turnpike. As a temporary solution, we pulled the fuse to make it stop, but we lost the central locking function and use of the fob. I later discovered than one of my son's friends (you know, the kid who can look at something and break it) had broken the lock on the passenger front door where the button protrudes through the door trim. I had that fixed, but when I replaced the fuse the erratic chirping and blinking resumed. My mechanic and I scoured the car for a short, but found nothing.

I am replacing the driver's seat on the 850 this weekend with a seat from a '98 V70 XC. My question is, can the security system be reset? If not, can I use the security module from the donor car for my seat ('98 V70 XC)? I figure, with the seat out, it will be a good opportunity to get up under the driver's side of the dash to pull the module from the donor car, and replace the module in my car before I install the new seat. Any thoughts out there? Thanks!

 

The 850 Alarm system is not compatible with the VGLA system from S/V70.

The 850 had 3 different alarms:
- Volvo alarm : it engages by turning the key in the lock and also with the Fob which has the 2 buttons placed in the same height

- Guard 1 : can be activated only by the remote and has a receiving panel placed in the middle of the A-pillar on the drivers side

- Guard 2 : can be activated only by the remote and has an Fob with two buttons different in size and placed one above the other.


Normally if everything works you should be able to kill the alarm with the Fob.

 

Scutyde,
Is there a way to reset the system with the key fob ( like by holding down the lock and unlock button at the same time)?

 

Unplug the siren. Problem solved.

 

Usually the alarm will activate the immobilizer. If the car runs with the alarm sounding something else is going on. I'll see if it's in my manual.

 

Unplugging the siren only addresses the noise issue. The lights still flash and other motorists think I am signaling for them to do something. I will check my manual as well to see what may have started this problem or, better yet, if there is some kind of reset

 

Reset is only possible if you take out the alarm relay and put the plug in Pos 210 otherwise the car will not start due to missing ground for the starter. Did you managed to start the car with the alarm engaged? This should not be possible normally.

 

Yes. The car starts normally and has for the entire time since this happened. The only solution has been to pull the fuse which disables central locking and the remote fob.