Dome lights flickering

1995 Pathfinder - My dome lights keep flickering and at the same time the dash light sometimes says a door is open. I can turn the dome lights fully off and stop those lights from flashing, but while driving down the road, the door open dash light sometimes goes off, sometimes comes on dimmly, some times comes on full bright. It seems to come on and off more when I hit bumps. I have checked all door switches and dome lights - no rust, no frayed wires anywhere I can find which could be grounding and causing this to happen.

The wiring diagram says there is a diode in the lighting circuit somewhere between the rear hatch switch and the front door switches. Perhaps that is faulty and makes it seem like a door is open. Does anyone know where that darn diode is? I can't find it.

Or - does anyone have a better idea of what might be wrong?

had same prob on 88 pthy it was the back door the switch is in the side of the lock mechanism on the rigth side if your facin the door