I may be in the wrong forum for my response but wanted to share. I went Googleing the net to find help with my issue and it led me here. I have a 2002 4runner Sport Edition. I too had the same issue with the theft deterrant light to the left of the steering column blinking when the vehicle was turned on. Over the weekend, the battery drained, and I assumed it was a malfunction with the alarm. I would drive down the road and the overhead light in the cabin would flash alternating with the open door red light in the dash, with the horn honking like the alarm was going off. People were afraid of me. My mechanic decided it was the alarm system and sent me to the local Toyota dealer. They determined that my mechanic had put too small a battery in the vehicle last time he changed it. 60mth warranty. I was 18 mths into it. Toyota upgraded me to a higher power Toyota battery [made by interstate]. All the various issues went away with no damage to anything. The door locks worked again. The alarm system worked again, correctly. The alarm light stopped flashing when the truck is running, and starts flashing when the alarm is armed. The horn honking and interior / dash light flashing all stopped. Really odd that low power can cause such malfunction, but apparently that was it.