I hooked up 6 exterior 55 watt light fixtures to a photo cell and cannot get them to turn on and when I change the wire on the photo cell, then they will not turn off. If I wire the light s without the lights work OK.

The feed must connect to the black and the load must connect to the red, along with a neutral to the white on the PC. If you have it connected in this manner, and covering the PC does not switch the lights on, then the PC may be defective.