2001 SAAB 9-5 Turbo sedan, alarm goes off randomly. I cannot lock the car at this point

The battery in the actual alarm is going bad. There is no way to prevent the alarm from going off short of removing the old alarm! I once was driving down the street with the alarm going off full bore. I tried all the gimicks and stuff on the net, but again short of pulling the alarm out it will continue to go off. Remember that the battery to the alarm is separate from the battery to your car so don't waist time looking at your car's electrical. You can look on youtube for a video on how to take the alarm out (pretty simple process), and you can drive around without the alarm no problem. If you want you can replace the alarm with a remanufactured alarm that has a new battery for pretty cheap.

Remove the plastic cover inside by the left front wheel. There you will find a plastic box. Open it with a screwdriver and you will find a small battery like in clocks. Replace it and glue plastic box together again. Simple and cheap.

You can disable the siren by pulling the fuse. The fuse also controls the AC so this is not something to di o in the summer. The fuse is located under the hood in the fuse box behind the battery. Consult your manual to see the slot that the fuse is in, In this way you can disable the siren while you decide if you want to repair or replace the siren. Note this works for the 9.5 Linear model. Not sure if it works for the aero engine.

Here are two links that will help you. First, a video for short-term workarounds: https://www.youtube.com/watch?v=TLYQ8VvEZlg and a full rebuild guide: https://www.youtube.com/watch? v=ibEWHXE3fSI