Can't figure out Ignition problem

Hello everybody, I have a 1994 Trans Sport, 3.8L, 130,000 mi, about 3 weeks ago I was noticing that my battery was drained every morning I went to start the car, and then after getting it started I removed the key and the car kept running, engine, electrical, everything...and most of the dash warning lights were on, (abs, low fuel, seat belt, etc.) I had to disconnect the battery to shut it down. So that weekend I replaced the ignition lock cylinder and the ignition switch, and at first the same thing was happening. Then the next day everything seemed to be working fine. That was for about a week, now this week it's doing the same thing. The only thing I can think of doing now is replacing the wire harness that goes to the ignition switch. Any suggestions would be much appreciated, thanks in advance.