Is there a way to disconnect security system,it may be causing my battery to die.

Is your battery original?
In good condition?
Are all cables clean, connected tightly and in good order?

How do you figure, John? Security is a passive monitoring system, not sure it represents any significant load on the battery. Check what Boosty said also.

trust me first thing I check is battery and cables,my wife figured out that when she locks the car that the rear passenger side brake light stays on sometimes.And I have seen the security light on while driving also 1 time I had a security system on DIC.I just thought I could pull a fuse and disconnect security just to illiminate it, not to just disconnect.My battery hasnt died as of late but we have caught the rear light on from time to time and my wife would lock and unlock(vice versa) it would turn off.Today I did a little tinkering (too cold) and I see wet snow or water is getting in trunk lid where light is so I thinkl I will investigate more.thanksMy wife drives the car all the time so its hard to diagnose, I get the 1990 of course.

In most cases with brake lights staying on, it'* the brake light switch sticking

This appears to be a much larger issue than simply unhooking the security system can correct.

Please list all the known symptoms and we'll ask for this to be moved to electrical for better exposure.

That tail light being illuminated sounds like water or snow related like you mentioned. I don't think the tail light & security light problems are linked in any way unless there'* water in close proximity to the trunk latch area possibly.

The only symptom we know is the rear passenger brake light and our battery dieing over night a couple of times.Noticed water dripping out of trunk lid one day where light is , I pulled out little rubber plugs so water can drain and no water is staying in trunk lid now.
The rear light will turn on out of the blue sometimes, and wife said when she locked it , it stayed on one time.We can go a week or 2 without light coming on, and the cold seems to play a part.

That'* very strange with out the brake pedal being depressed. The brake lights are in a parallel configuration also. the next time this phenoma occurs, remove fuse #19 ( STOP LP fuse) in the rear fuse block and check to see if the right rear brake light goes out.

Ok Mark thanks ill try it.This morning I had security system on DIC again but no light.