MrsFlynn and I did some testing tonight and we discovered how to fix the problem without replacing the lights.
![Smiley :)](https://www.carls-sims-4-guide.com/forum/Smileys/default/smiley.gif)
We tried resetting the lot with MasterController but it didn't help. So, we tried one other thing: resetting the color of the light:
- Click any light on the lot.
- Click Color.
- Pick any color from the wheel menu.
The lights will now show correctly.
Why this happens in the first place? Not sure, but it seems to have started with houses created before the patch that included the improved graphics engine -- 1.26 for Pets? In any case what I'm thinking is that the lights on the older lots are somehow set to color code 0,0,0 (black) and/ or the light's intensity is set to 0. In my test house, I checked the light's color and it was set to White (255,255,255). I then checked the Intensity and it was set to 0. Ah ha!
So, it looks like when the graphics engine was updated there was a bug in the routine to calculate the intensity of the lights for houses created before the patch. Houses already placed in towns and in the Library seem to update correctly, but houses imported in from Sim3Pack file seem to have the light bug.
Hope this helps everyone having this problem.
![Smiley :)](https://www.carls-sims-4-guide.com/forum/Smileys/default/smiley.gif)
Flynn and MrsFlynn