1992 Oldsmobile Eighty-Eight - Electrical Problems

First off, I am not an expert when it comes to cars, but I can kinda muddle my way around on a car. I have a 1992 Oldsmobile Eighty-Eight with a 3.8L and has about 210k on it. Back in the fall, my windows/power mirrors/power seat stopped working. I happened to drive on a bumpy road and they began working again. At least for a little while anyways.

I am currently trying to at least fix the windows. I opened up the rear right passenger door in an attempt to place direct power to the motor and then place a switch on the dash to control it. Before I got to that point, the rear right window began working. I then went into the drivers side door to check if there was something wrong with the master controls. After some fiddling with stuff and finding that the circuits appeared to be intact and had 12V running where it was supposed to be going, the rear windows and drivers side window began working.The passenger side door is still a mystery. It has 12V running to the motor and the voltage drops to around 7.6 to 8V when the switch is depressed, but nothing happens. The mirrors and seat also began working again.

Is it possible that the ground is partially corroded and that is the reason for the miracle recovery of some of the functions? I dug around under the driver's side rug to look for the ground bus, but could only locate a large bundle of wires in a black plastic sheath. Is it located inside this bundle?

Any help would be greatly appreciated (Sorry about putting in my life's story there)

Open the harness and look for a multiple ground splice.

Thanks Max, I dug some more rug and found it further along the wire harness than I expected. It was about even with the parking brake pedal and it was underneath the wire harness. After some cleaning and soldering, everything seems to be working fine *crosses fingers*