How to Find Out if the problem is the Photocell or the wiring is Photocell showing 0 or 1020 On PCC1 or PCC3 (ONLY) all the time:
1. Try Moving the knob under the connection of the PHOTOCELL in PCC1 or3 Card Clockwise a Counter Clockwise a little at the time and look for the on board photocell reading to see if it increases or increases. If this works adjust as needed based on the illumination of Outside.
2. In PCC3 If you did not get any reading Remove the Plug from the Input 1 and try Input 2 or Input 3 and check the reading if it worked in any change the setting to reflect the working input.
3. If option 1 and 2 didn't work Remove the Photocell from the roof and connected directly to the input of PCC1, or Bluebox Master or Input 1,2 or 3 of PCC3 Cards and check the reading?
If it worked then the issue is the wiring. If it still shows 0 or 1020 You have a Bad Photocell Card.