Current draw need help

[Jaysonb]

I have been getting my 80 c10 in good enough shape to drive for the rest of the fall. I put a new battery in it, and in a few days it was dead, I charged it up, same thing a few days latter. I got the meter out, and found a .9 amp draw, and narrowed it down to the heater circuit. It seems to have 12 volts going to it with the key off, looking at the wiring diagram I dont think that it should. So I just put in a new ignition switch, and there is still power going to the heater circuit with the key off. This is a non ac truck. It seems like a pretty simple circuit. Any ideas???