I took the NEG battery cable off and put a test light to the NEG side. The BCM (on the pass side behind the glove box) began to click. I unplugged the large blue harness first. It stopped clicking but then my headlight motors started clicking. I unplugged the headlights and plugged the blue connector back it. The BCM started clicking once again. I unplugged the large blue connector again and left the two smaller ones in the BCM. The clicking stopped but the test light still had a very faint signal. I unplugged every plug in the BCM and still had a very faint signal to my test light.

What is my next step?

 

As advised previsouly, you need to add a "Signature", with basic info about your car - year, model, engine, trans, major mods.

 

It turns out it was the aftermarket radio. The guy I bought it from said that it had these problems before he installed the radio but failed to tell me that he took out a different aftermarket radio and installed another one incorrectly. Re-wired everything correctly and problem solved...