Alarmed

Still having electrical problems with my 940. Have now picked up an 850 and put the 940 off the road and bought a voltmeter. Fully charged battery, fitted to car, read 13 volts. Good Disconnected battery car stands for 6 days re-connect battery voltmeter still 13 volts car starts fine. Leave battery connected for five days check with voltmeter and reads 12.5 volts still within limits I would think. Turn key one sluggish turn of engine alarms sounds will not turn off with fob disconnect battery. Every time I try to reconnect battery alarm sounds neighbours getting fed up with noise. Even if I now wanted to try replacing ignition switch or even start motor I can't reconnect the battery with the alarm sounding. I guess I can remove the siren but can I disable the alarm/immobiliser? It is a Volvo alarm although I see no name but numbers such as 03 S545006 or 7 03 8506 02 LK. I can see two blue/red wires 2 yellow/red and 1 white green. Car is a 940 se auto 1993 Silence would be golden!!!! Just found and tried someones trick turned ignition on and then re-connected battery - ah - silence. Then put voltmeter on and lo and behold 10 volts. Battery now on for recharge before starting quest again tomorrow. Any clues?

the alarm defaults to ON when it gets power yoiu need to turn it OFF just after you connect the battery before it goes off . I suspect your battery is faulty , yes 12.5 volts is just ok but under the load of the starter it may drop to 8v or so . try it ......

Cheers In my ignorance I thought 12.5 was good. But have had previous problems resulting from printed circuit board on instrument cluster which have now been resolved but looks like I wrecked the battery in the process. Found a trick on the 850 board of turning the ignition on before connecting the battery and got it connected without sounding the alarm. I could then get my voltmeter on and it was down to 10 volts. Looks like I now have battery problems then. Thanks

12.5 is ok but 12.75 is good temperature is a factor too ! today 12.5 would be good !

I really can't help with the alarm problem but I would disconnect the alarm horn before trying it again.

Can't speak from Volvo experience, but wifey had a BMW Mini, which had a factory fault which flattened the battery. Each time you tried to open the doors, the alarm would go off and it couldn't be stopped. So what has been said before makes perfect sense. Good luck.