so I have done this before on different trucks in the past. you take the pos bat cable off and put a test light between the bat post and terminal end right? ( with everything off ) and see if the test light glows. well it does, so to check my procedure I tried this on another truck I have and it lit up also. am I doing some thing wrong? did this only work with older trucks? because I am thinking the radio clock constant and maybe the pcm are always drawing something. I could start removing these fuses but eventually it's going to defeat the test. thanks for any input.

 

all modern vehicles will draw current through the IOD circuit (ignition off draw). like you said, it includes radio, pcm, security, etc.

you could try removing that fuse to kill the draw. i'm not sure if its in the end of dash, or pdc box. i'd guess pdc box first.