Battery keeps draining (HELP)?

[Sooner1970_K10]

Ok. I bought the truck and it ran fine for several months. A few months back I put a new Sanyo dual shaft style radio in and it worked for a couple of months and then died. I havent needed the truck for anything and tore the dash back open to try and find out why the radio died. At this time the radio is unplugged from its wiring harness but something is still drawing from the batter. I replaced the battery and the new battery was dead in 2 days time. What exactly am I looking for? Does a hot wire have to be grounded to drain the power? I am just looking for useful tips in how I should go eliminating what is causing me this problem. I am about 95% sure it has to be something I have caused up under the dash. However around the same time the problem started I had also reconnected the tail light wiring that had come disconnected at the firewall and also cut out an aftermarket camper plug that had been mangled all to hell.