I have a 2000 jeep Cherokee. So today every time I turned off my jeep after a few seconds the alarm would start going off. I thought this was because I had stepped on the key fob a few seconds before but after I took the battery out of the key fob it still does it, I took the horn fuse out for now so it can't go off but what could this be???

 

Check your battery cables for any corrosion and correct also you will want to clean your engine and chassis grounds...