I'm Neal and I am here to assist you. Only accept when you are happy with my assistance. If I can't help I will open your Question to other experts.
I'm sorry but the alarm system is designed to be tamper resistant, if you could just pull a fuse a thief could do the same and alarm would be useless.
Is the car actually starting and running?
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I assume you tried locking and unlocking the car with the key?
Have you closed the hood? There is a sensor that triggers the alarm if the hood is opened under certain conditions.
If the car is not immobilized, the alarm should not be going off, did the fob just die and all of this started at the same time?
Ok then it seems there is going to be a problem with you alarm system like a bad module. You could disable horn by directly disconnecting it if that would work for you.
It is about an hour of work to get to it. it is #12 in this diagram
12 - Anti-theft alarm horn - Installation position: In area of C-pillar covered by trim
Just another way of doing the same thing, I was just going to have you disconect it directly from the horn. As I usually repair these and not disable them I was not familiar with that method.
I have never disabled one for anyone, usually that is something an owner will do themselves.