Photo-Cell not working

[alrha]

I have my photo-cell plugged into my controller, but even when i keep it in the cabinet under my tank with absolutely no light, it still switches between full power and lower power rather than remaining on the low power only at night.
am i doing something wrong?

 

[rvitko]

Usually this occurs because the photocell is not fully inserted. On some units the board doesn't perfectly line up with the hole and a little effort is required to fully insert the connector. If you have an Ohm meter the two pins that are on one side of the connector are the energized ones. You should read about 19 KOhms with darkness and 49 Ohms in light. You need really steady hands to check this because if both probes touch the grounding shell you will get a false reading of almost 0 Ohms. Please also try disconnecting all power to the controller and restarting it, sometimes it won't recognize something connected while the board is energized. Do you have a single or multicontroller? Let me know what results you get. Unfortunately short of testing the ohms of the photocell it is nearly impossible to determine if the fault is in the photocell or the controller.