I checked the light fixture wires carefully last night. The wires were fine, but when I removed the pull chain switch and checked for continuity, there was none. Unfortunately it was a sealed unit. I figured it was bad and drilled it out. Indeed it was. There was evidence of overheating/burnt connection and too much distance between the contacts. I'll try to replace this, but I'm sure this is the problem. It makes sense. Again, Thanks for your help.