Is it a steady blast or an on/off pattern? Any areas serviced recently, or horn issues just appeared? The horns were blowing the fuse, replacements operate, but has a new issue. That's kinda strange. Solve for - when key is inserted, the horns have a party. First, I'd change keys to make sure it's reading the code. I've tripped the alarm opening the unlocked door after a batt. swap. Closing the door and rotating the door keylock made it happy. Never tried the Fob and don't carry one on the ring. Heard a lot of horn action and marker flashing getting it to shut-up inside my garage.
This >> 'I think you have to unlock the door with the key to disarm' Seems to be a trick that works at least when Fobless. Give her a couple rotates before inserting the key. Remember mine was unlocked when 'breached' so the alarm logic goes nuts after a batt. pull.
I don't understand 'removed the air bag'. The fuse?