Thanks for using Just Answer for your needs. Have you had a Parasitic Load test performed yet?
This test should have been performed already if you have had repeated battery draining. What this test does is measure how much amperage is being drawn from the battery when it is just sitting there like it does overnight. It should have no more than 150 milli amps of parasitic load.
(i.e. a Parasitic load is any load that is not supposed to be there, kinda like leaving the door open and the Dome light stays on.) That load can be measured and if the test shows more than 150 milli amps, then you can start pulling out fuses to see what circuit the load is on. When you pull the fuse with the load, the milli amp parasitic load will disappear.
I apologize for not being clearer. The kill switch would not cause this or be involved here. Also, yes, you should have the parasitic load test performed at a repair shop. The best place to finally get this fixed is the Dealer. They will usually charge for 1 hour ($75) to perform a parasitic load test as well as check the battery, charging system and all the wiring. This will at least give you an idea as to what is causing this problem.