Parasitic Battery Drain

[reevesjo]

1999 Silverado, 6.0L, 2WD, Long bed: Looking for battery drain problems. I see no problem when I remove the engine compartment fuses one at a time. I am now trying to check the driver's side interior fuse box. I could not find the door switch to keep the interior lights from coming on. So, I removed the 15a courtesy fuse in the engine compartment fuse box. When I removed this 15a fuse, the dashboard "Security" light still flashes. How can I disable this light so I can proceed checking for battery drain? I can't find it in my Haynes book electrical diagrams.