battery draw

[67Fleet]

Well, I posted a while back about my battery draining, got the problem fixed, and now I've got another skeleton in my closet. I'm pretty sure I've got a draw somewhere but not positive. My battery died a week ago, so after every time I drive it now I unhook the - terminal when it's parked in the garage just in case. Tonight I took out my test light and with the - batt cable disconnected, I clipped the test light cable to it and probed the - terminal on the battery. The light barely lit up for like a split second and then went out. I had a good connection on both ends. Why would it not stay lit? I tried again, but nothing. I thought ok, maybe I blew the bulb. So I put the clip on the + side and probed the - side and it stayed lit. I again clipped the clip to the - batt cable and probed the - terminal. Nothing. Any ideas???