'97 Blazer with ghosts in the doorlocks

I just now registered, but have read many threads. I have MANY issues with this truck, but will start with doorlocks. With either the remote or manually, they all seem to do whatever they want. The back hatch (opens upward) will not unlock, but the rear window will. I was able to get to the latch lock and rig it with a coat hanger (can be pulled up or down via the glass access). I can hear the actuators trying to work, and the locks will "twitch", but they simply act crazy. It's almost as if they don't have enough voltage, but batt is new due to ECM issues. Any words of wisdom? Thanks...