Why does the photo cell not work. I have tried 2 different transformers with the same result. Lights come on in the on position, but not in the auto

Make sure there are no bright lights shining on the photocell. Check and see if there is a sensitivity setting on the unit anywhere. On my lighting set the photocell is part of the power pack.

Make sure that the built in photo eye is not in a shady area. For example if it is behind shrubs or plant material that hides the sun the photo eye cannot sense enough light. In the auto position the transformer will not turn the lights on until it stops sensing light. Place the transformer in the auto position and you can test the photo eye in the day time by putting black electrical tape over it to simulate night time. Or at night time you can use a flash light to simulate day time etc..... Understand there is a 3 to 5 minute built in delay for the photo eye to turn on the transformer in the auto position. The transformer that comes with the kit has the built in photo eye. Also make sure that at night time there are not any lights shining onto the photo eye. This may cause the photo eye not to work properly.