96 850, I have the light on the top of the dash, it doesn't blink, have the remote fob that Volvo list as the basic alarm fob, I don't see anywhere that its supposed to honk, but the light on the dash is supposed to flash if anything is tampered with, the alarm relay is there.

Is it supposed to honk? From what I've found if I have the light on the dash and the fob I should have some sort of alarm. tried opening the doors, the hood and trunk with it locked and nothing happened, left the window open and opened it from the inside and nothing happened either! Am I missing something? Any help is appreciated, thanks!

 

The alarm horn on those cars is mounted on the firewall - and falls apart.

 

Do you know if the alarm works? Does the fob lock/unlock the car? Have you checked the batteries in the fob?

The dash light should flash when armed. Once the car is locked with the fob it should deadlock the car and you should not be able to open the doors from the inside or through an open window.

When you press the fob buttons you should hear a very quiet chirp from the fob to let you know it works, however it may need to be reprogrammed to the car. It could be a fob from another car that someone has put in with the car when selling

If the car locks with the fob and the alarm sets then after 30 seconds if the car is opened with a key the alarm will activate and the alarm horn will sound

 

Fob works, just found out it does have an alarm, so it used to work. It has the original remote. Ive replaced batteries cause it would take forever to lock when the button was pressed. The car has been in the family since new. I tried waiting 30 seconds after locked it and nothing happened. Im going to try what hoonk said, maybe the horn in the front deteriorated…

could me using a lock mechanism for the rear hatch from a v70 cause any problems?

 

Alright, new theory, i got into a little collision and the hood latch on the driver side got messed up… didnt realize that was part of the alarm system. thinking the contact in it isn't contacting, otherwise all the mechanisms should be working for the doors etc. Pulled the body out today and mounting the new fender, with it all together hopefully it works, if it doesn't ill go deeper into everything and give an update! Thanks for the ideas so far!

 

Easy to bypass the connection for the bonnet latch to assess whether it is causing the fault

 

Put it all together and still no alarm, gonna bypass the hood like you said, if its not that im thinking it might be the trunk, i know the wires wear out where it pivots.

 

Also worth checking continuity between the door latches and alarm module