Door locks intermittent

Yet another door lock dilemma. My 99 burb seems to decide on its own when all of the door locks want to work. I have noticed that in the morning, prior to any warming of the body/frame form sunlight or engine heat, the door locks seem to work well (except the pass front-its a sticky actuator rod/unit I'm guessing). But after sitting in the sun, only the drivers door and pass rear door work (rear barn doors are no problem). There is a lot of forum chatter about the actuators, which I plan on checking, but does anyone know anything about the body control module, which I understand controls the door lock functions? I am curious as to whether there is a ground problem to this unit that fails upon heating up. FYI-the key FOB and main drivers lock switch show the same problems, so it's not the FOB. Words of wisdom are greatly appreciated.