Help please,

I have a 1999 chevy blazer LT 4.3l

Ok, so my alarm keeps going off at random times. I had the battery checked to see if it was bad and it was, so I had the Napa put in a new one. Was hoping that this would work, it was fine for about a week then the alarm went off again for no reason. Had the battery checked again along with the alternator. Battery was at 615 cranking amps, should be 815. The test came back as a bad battery. The test on the alternator came back with flying colors. So now I am thinking that something is wrong with the alarm system or maybe something is drawing power from the battery while it is shut off.

Does this blazer have a hood switch, tried looking it up, but nothing came up.

Not sure what I should do. IF anyone has any suggestions on what my next move should be please help.
THanks