Have you tried Resetting Preferences?
I don't know what version of Photoshop you are using, so hold down Cmd-Opt-Shift when starting Photoshop and delete the settings file and let Photoshop keep loading.
I have a Macbook Pro that uses a HD4000 and Lighting Effects works on that card. My MacOS is 10.12.6
In recent versions - Lighting effects uses the same engine as 3D. Do you have the 3D option or is that also greyed?
Rather than ask many questions of your system and set up, can you go to Photoshop >Help > System info press the copy button and paste into this thread.
Thanks Davescm, the answer above corrected the issue. Regards
It corrected the issue. Many thanks.